John Guest Speedfit 3/8 Inch Compression Female Connector, Push to Connect Plastic Plumbing Fitting, White, PSEI6012U9P

After multiple trips to the local hardware stores, I finally found what I actually needed on Amazon. I recently moved into a new house and had an RO installed the day after we moved in. I needed to hook up my RO to my refrigerator water supply line and was having no luck whatsoever finding the hardware to get it done. My RO is the APEC RO-HI (purchased from Amazon) with the 3/8" tubing for faster water dispensing. On new house builds (at least in AZ) the builder is installing 3 standard water valves under the kitchen sink area. 1 = hot, 2 = cold, 3 = refrigerator water line feed. By default the builder will use a 3/8" to 3/8" compression hose to connect valve 2 (cold water) to valve 3 (fridge water feed). I tried finding the standard tube compression fittings with nut & ferrule but I just couldn't seem to find the right part. I finally searched Amazon and found this 3/8" female compression to quick connect push-in tubing connector and it was exactly what I needed. The connector screws onto the standard 3/8" compression male adapter of a water valve and the other end accepts my 3/8" RO water line tubing. From the attached picture, you can see the connection to valve 3 (fridge water supply feed) on the right. This connector is attached directly to the water valve. You can't see it, but I cut a small piece of tubing and attached this connector to a 90 degree connector to eliminate extra strain heading up to the additional T connector on the clear tubing. The clear tubing is the filtered RO line going to my RO faucet. By adding the T connector, I have good water going to the RO faucet and into valve #3, which feeds my fridge water source. I added some Teflon tape to the valve 3 male end and hand-tightened this connector. No leaks and perfect result. Highly recommend this product if you need to connect your 3/8" RO tubing to your standard 3/8" compression male valve. A++

Having a water filter installed under my kitchen sink, this adapter was the perfect piece to fit between my 3/8 cold water line output and the water filter. While not required as the filter came with a kit that would allow the red line to be clamped down with tightening force on the outlet, I felt much more assured having this piece simply go in and be done with it. Not tools required to screw it on. Simple hand turn until no longer turns, and push your red line tube in. Simple as that. Check for leaks once water line open, and call it a day. Don't lose the small rubber ring that it comes with as mine fell out causing a leak but I quickly noticed the black piece on the counter and reinstalled with no issues.

I needed this to connect my Waterdrop filter system to the water drinking faucet. Worked great for my job. No leaks and easy install.

I was hooking up a new under sink water filter. The fitting that came with filter was no bueno. So, I went to the two big box home stores in town. The orange one had a helpful guy that told me they were out of the part I needed. The blue store had no help and no parts. Amazon for the win! This part was exactly what I needed and it works perfect! And because I'm prime, it got here next day - even though I ordered late in the day. The kitchen is back to normal, the water is flowing and the fam is happy. Wahoo! Thank you!

I have great confidence in John Guest fittings for push-connections. These are great when connecting plastic tubing like 3/8 pex lines for a filter or RO system. I trust these more than using a plastic ferrule and nut on a compression connection, particularly with plastic (even with the insert). I've used them in several places under my sink and behind my fridge and never had a leak. I do also use the locking rings that you can buy separately in 1/4 and 3/8 sizes just for added security and they worked fine with these connectors.

This works a charm to go from angle valves (3/8" compression) to the typical push to connect lines. Used this to connect a Reverse Osmosis filter system to the customary angle valve. However, I had to use an adapter to reduce the PTC side down to 1/4". Oddly the description does not mention the size of the PTC connection, which delayed my installation further as I waited for the reducer. Finding this type of small piece at the big box stores is a bit hit and miss, and I was not in a particular hurry, but still would have been nice to know connection type on both sides. One star off for lack of description.

So far, so good! No leaks! Perfect attachment to go with a 3/8 tee stop valve for my water filter.

Easy to install, works great and no leaks

Worked perfectly for my RV water filter system.

Fitting leaked at the push to connect end. Was installed properly. I have used John Guest and similar type fittings in the past. I am familiar with proper installation procedures. Was disappointed.