PI251212S John Guest 3/8in Hose ID to 3/8in Stem Adaptor

The John Guest PI251212S adaptor has a 3/8in hose barb at one end and a 3/8in push-fit stem at the other, letting you connect 3/8in ID hose directly onto a 3/8in push-fit tube or fitting. WrekinWater supplies this for jobs where you need to join flexible hose to a rigid push-fit system without changing bore size, such as connecting an RO unit's tubing to a length of hose. The barbed end is designed to be secured with a hose clip.

When you need this fitting

• You need to join 3/8in ID hose directly to a 3/8in push-fit fitting or tube.
• Your current adaptor has split at the barb or lost its grip on the hose.
• You're extending a push-fit run with a short length of flexible hose.
• You're servicing an RO or filtration system and need a matching same-size adaptor.

Even though both ends of this adaptor are nominally 3/8in, they're two different connection types: a barb that the hose stretches over and grips, and a stem that pushes into a collet fitting. Confusing 3/8in hose ID with 3/8in tube OD is a common mistake, since they're not interchangeable, so it's worth checking which measurement your existing hose or tube actually uses before ordering.

WrekinWater has supplied genuine John Guest fittings to water treatment customers for 15 years from our base in Bettisfield, Shropshire, and we're rated Excellent on Trustpilot. Getting the barb and stem sizes matched correctly from us saves a second trip when a generic part doesn't quite fit.

How to fit it

1. Cut the 3/8in push-fit tube square and deburr the end, if connecting into further pipework.
2. Push the stem end fully home into the mating push-fit connection.
3. Tug-test the stem end to check it's seated correctly.
4. Push the 3/8in ID hose fully onto the barbed end.
5. Secure the hose with a hose clip.
6. Run water through briefly and inspect both ends for leaks.