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1/4" NPT Air Compressor Water Separator - 150 PSI Professional Filter System (AI303-C1)

Regular price $17.99
Sale price $24.99
🛡️ 12-month satisfaction guarantee 🚚 Free US shipping 📦 Arrives in 3–5 business days★ 4.74/5 (110 reviews)
FREE shipping on every order No minimum · ships free anywhere in the US
In Stock — Arrives in 3–5 business days Free shipping on every order.
🏭 Factory-direct from LE LEMATEC — manufacturer pricing, no retail markup.
That’s $7.00 (28%) below typical retail.
🔒 Secure checkout · 🔄 12-month satisfaction guarantee
What buyers say
Verified by Judge.me
★★★★★
GYVerified
Awesome job
Did an awesome job on any moisture that might have formed in the line. Three panels in Texas humidity and no water issues.
★★★★★
DomVerified
Easy to install
Works great and was easy to install. The filter has reduced the amount of condensation in my air take.

Inline water separator that catches moisture before it ruins paint or rusts tools — push-button drain, Teflon tape included.

1-micron filtration2–150 PSI1/4" NPTAluminum + brassTeflon tape included

✔ Threads inline at the tool or compressor outlet · 🛡️ 12-month guarantee

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12-Month Satisfaction Guarantee — replacement, exchange or refund.

AI303-C1 air compressor water separator 1/4 NPT - front view showing full product design
1/4" NPT Air Compressor Water Separator - 150 PSI Professional Filter System (AI303-C1)
Regular price $17.99
Sale price $24.99

Product Summary

The Le Lematec AI303-C1 is a 1/4" NPT air compressor water separator rated at 150 PSI. Aluminum construction with manual drain valve and clear inspection bowl. Removes water and particulates from compressed air lines. Factory direct from Le Lematec.

Best for: Budget-friendly moisture protection for air tools, spray guns, and pneumatic equipment.

Air Compressor Inline Filter — Remove Moisture & Oil Contaminants

Professional-Grade Water & Contaminant Removal for Peak Air Tool Performance

This high-efficiency water separator delivers pristine, contaminant-free air for all your pneumatic equipment. Built with premium aluminum construction and brass fittings, it features a 1-micron filter and one-way valve protection, operating seamlessly at pressures up to 150 PSI.

Professional Features:

  • Advanced Filtration: Reusable 1-micron filter removes water, oil, and dirt
  • Quick-Release System: Push-button drain valve for effortless maintenance
  • Safety Design: One-way valve prevents damaging backflow
  • Universal Fit: 1/4" NPT male and female connections
  • Premium Build: Aluminum body with solid brass fittings

Technical Specifications:

  • Maximum Pressure: 150 PSI
  • Operating Range: 2-150 PSI
  • Connection Size: 1/4" NPT
  • Filter Grade: 1 micron
  • Construction: Aluminum/Brass
  • Drain Type: Push-button valve

Package Includes:

  • AI303-C1 Water Separator
  • Teflon Tape
  • Male Connector
  • Installation Guide

Ideal Applications:

  • Professional Workshops
  • Construction Sites
  • Automotive Garages
  • Vehicle Air Systems
  • Industrial Settings

"Perfect for onboard air compressor... removes all water I was seeing before" - Verified Purchase, May 2023

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Frequently Asked Questions

Q: What does a water separator do for my air compressor?

A: A water separator removes liquid water and oil droplets from compressed air before they reach your tools. Without one, moisture causes rust inside air tools, fisheye defects in paint finishes, and premature wear on pneumatic equipment. The AI303-C1 uses centrifugal separation and a 1-micron filter for effective contamination removal.

Q: Where should I install the AI303-C1 in my air system?

A: Install the AI303-C1 as close to your air tools as practical — after the compressor tank and after any main-line piping. For best results, mount vertically with the drain bowl at the bottom. If you have a long hose run, install at the end near the tool connection point.

Q: How is the AI303-C1 different from the AI303?

A: The AI303-C1 is a compact water separator with 1/4-inch NPT connections optimized for single-tool installations. The AI303 is a larger inline filter system with push-button drain and 1-micron filtration. Choose the AI303-C1 for individual tool protection and the AI303 for main-line filtration.

Why Professionals Choose This Tool

  • Water Separator Technology: Centrifugal action spins moisture out of compressed air before it reaches your tools
  • Teflon Tape Included: Everything needed for leak-free installation in one package — no extra trips to the hardware store
  • Compact 1/4" NPT Size: Fits standard home and small shop air systems without adapters
  • Clear Bowl: Visual inspection of water level without disassembly

What's in the Box

  • AI303-C1 water separator filter
  • Teflon tape for leak-free installation
  • 1/4" NPT fittings
  • Mounting bracket
  • User manual

Compatible With

Air Compressors Any compressor with 1/4" NPT outlet, up to 150 PSI
Air Tools All 1/4" NPT pneumatic tools
Installation Inline between compressor and tool or at point-of-use

Ideal Applications: moisture removal, tool protection, home garage air system, small shop filtration, inline water separation

What is the difference between a water separator and a desiccant filter?

A water separator (like the AI303-C1) removes bulk liquid water using centrifugal force — it catches about 90% of moisture. A desiccant filter uses chemical media to absorb remaining water vapor for near-dry air. For most shop use, a water separator is sufficient. For spray painting and sensitive applications, use both in series.

Does this filter remove oil from the air?

The AI303-C1 is primarily a water separator. It catches some oil droplets but is not a dedicated oil removal filter. For oil-free air (needed for painting and food-grade applications), add a coalescing filter downstream.

Related Guides & Resources

Customers praised this professional-grade moisture separator for effectively removing water and condensation from air lines, particularly for painting, sandblasting, and air tools. Most noted "excellent quality" metal construction and easy installation. However, some concerns about occasional leaking issues and one report of reduced air flow. Overwhelmingly positive ratings highlight reliable performance.

  • Excellent filter. My spray finish improved dramatically.
  • Housing is made from metal, not plastic. Appears to be excellent quality.
  • By far one of the best in-line filters I've ever used.
Quality (positive)Drain (positive)Water (positive)Moisture (positive)Separator (positive)
  • 5 stars: 89 (81%)
  • 4 stars: 17 (15%)
  • 3 stars: 2 (2%)
  • 2 stars: 0 (0%)
  • 1 star: 2 (2%)
E
Eric Marshall
Works Good, not Great!

I do a lot of sanding and polishing with my die grinder. Condensation is not good when refinishing metal, part of my problem was using a front exhaust die grinder, so I purchased a rear exhaust die grinder and this filter. The filter does work but does not filter all condensation unfortunately. I thought it was because the filter was filling up, but when I attempt to drain there is nothing there. It's not a huge problem, but I thought for sure for the cost it would be better manufactured than the cheaper alternatives. Having the rear exhaust die grinder helps, but the filter does not work 100% for the reason I bought it. I do not think I would purchase this again and certainly would not recommend it to my friends.

A
Amazon Customer
Easy for someone green.

I am a complete beginner when it comes to air powered tools so the easy installation was appreciated. It is also easy to use. I have only used it a handful but the filter seems to work nicely.

j
jason filipovsky
Best bang for the buck

Worked great blew all moisture out of my line before my paint gun. Helped me spray clear flawless

J
Jim Sproule
It's a great filter for the money

The filter worked great. I use this filter with my plasma cutter, It works great no problems with water or oil in my air.

C
Chris B
Excellent filter

Excellent filter. My spray finish improved dramatically.

T
Tim R
Great value

Great value. Very effective at removing moisture.

A
Al W
Works perfectly

Works perfectly on my spray gun setup.

S
SandblasterJoe
Good separator

Good separator for the price. Does what it should.

R
Rick T
Quality product

Quality product. Well made and effective.

P
Painter Pete
Essential for painting

Essential for painting. Catches moisture that other filters miss.

J
Josh M
Compact and effective

Compact and effective water separator. Push button drain is convenient.

S
Steve
Good filter

The filter worked well. Kept a lot of water out of the line. Good customer service.

G
GY
Awesome job

Did an awesome job on any moisture that might have formed in the line. Three panels in Texas humidity and no water issues.

D
Dom
Easy to install

Works great and was easy to install. The filter has reduced the amount of condensation in my air take.

S
Steven A. Smith
Air Compressor Water Separator

Nice product. Housing is made from metal, not plastic. Appears to be excellent quality. Plunger is spring loaded.

E
Emily Udvardy
Humidity

Working great to remove humidity from my sandblaster

A
Amazon Customer
Leaks!

Need this to NOT leak but it leaks. The package it came in was also crazy old so maybe the seals are crusty. Either way it does not work

D
David Lancto
fits great

works well no water in airline

j
jim
air line water separator

Nice product, not often I,m surprised by quality.

B
Bill K.
Great filter!

Works great with my new compressor!!

D
Dominique Martin
Great product!!

Filter keep moisture out of compressor and anything I inflate

A
Amazon Customer
Very useful design

Great product and very good quality working as it should

J
John B.
Good to Have

Works well, easy to install and use....stops my compressor becoming a water pistol in the hot and humid in East Texas climate.Use plenty of PTFE tape and don't over tighten ( thin threaded walls may split)

J
James Hauser
Does not work.

This is supposed to stop water from getting through. It doesn't. I use my compressor for blow-drying parts and this filter still lets a mist of water through it. To be fair, I think it maybe stopped some of it. It seemed like a little less water was getting through. But a little less does not help me. Or maybe the air was just a little less humid the day I installed this.

T
Tim
Quick delivery

It is working like it is supposed to work.

J
J.Nguyen
Good

Easy to install. Works as advertised. Would recommend

J
Jordan Saldana
Moisture removal

Removed moisture well and improved the performance of our blasting cabinet.

J
Josh J. Carruth
Will need a few male and female fittings.

Works great and allows for fast movement between tools

R
RWilson
Onboard air

Perfect for the onboard air compressor for my truck. I put it in line between my compressor and tanks to keep them dry. I can easily reach the purge button. My seems like it is removing all of the water I was seeing before.

J
Jess Mohler
Works well!

Does it's job of keeping oil and water out of my tool!

Shipping Information

  • Free shipping on every US order, with no minimum.
  • Most orders arrive within 3–5 business days.
  • Items marked factory-direct ship from the Le Lematec factory and arrive in 10–15 business days; an express upgrade to 3–5 business days is available at checkout.

Product Return/Refund and Exchange Policies

At Pro Air Tools, we ensure that we are providing the best quality products from the most trusted hand tool brand. Thus, we stand behind all of our products and quality control 100%.

In the event that the products you ordered from us did not meet your expectations, we will gladly offer you our 12-Month Satisfaction Guarantee — replacement, exchange or refund, with no restocking fee. 

If within 12 months from your purchase, you are not fully satisfied with any of the products, you may request any of the following:

  1. Product Replacement
  2. Exchange the product with another product of the same value. 
  3. Refund the amount you paid.  

Proof of purchase from Pro Air Tools is required for all return, refund, and exchange requests. We also require anyone who wishes to return a product, or request a refund, to fill out our Return/Refund Form. We will notify you via email or phone once we process your return/refund request. Refunds will be credited to the original payment method.

With regards to product exchanges, please note that we only accept this type of request if the product delivered to you is defective or damaged. If a customer opts to request a product exchange with “change of mind” as the reason, the product must be returned in its original packaging. The product should not be used or installed in any manner. All return shipping costs will be shouldered by the customer. Return unused product to our office address at 103 Edwin Pl. Asheville, N.C. 28801.

If you have any question regarding our return/refund and exchange policy that was not answered here, feel free to reach out to us via: 

Email at sales@proairtools.com

A phone call at  +1 828 398 0334

PO Box 8367
725 MERRIMON AVE
ASHEVILLE, NC 28804-2447

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