3/8 Stem to 3/8 MNPT

Bridge the gap between quick-connect tubing and threaded pipe with the Parker 3/8 Stem to 3/8 MNPT adapter. One end is a 3/8" stem that plugs into a push-to-connect port, while the other is a 3/8" male NPT thread that screws into standard threaded fittings, valves, or housings. Parker Hannifin molds it from sturdy POM polymer, and it weighs a scant 0.01 lbs, making it an effortless way to tie two different connection styles together.

• Stem x male NPT (MIPT) stem adapter
• Size: 3/8" stem to 3/8" MNPT
• POM polymer body resists corrosion and scaling
• Connects quick-connect systems to threaded plumbing
• Compact, lightweight, and easy to install
• Reusable stem side for flexible reconfiguration
• Threads into standard valves, housings, and fittings

Stem adapters like this are indispensable when a water-treatment system mixes tubing-based and threaded components, which is nearly always the case in real-world installations. This fitting lets you transition cleanly from a push-in manifold or quick-connect device to a threaded port on a filter housing, ball valve, pump head, or storage-tank fitting, all without resorting to a stack of multiple couplers that add cost and leak points.

For a reliable seal on the threaded side, wrap the male NPT threads with PTFE tape or apply a suitable thread sealant, then hand-tighten and finish with a gentle turn using a wrench, taking care not to over-torque the polymer body, which can crack if forced. The stem side simply plugs into its matching quick-connect port and locks in place automatically; press the collet ring to release it later if needed. With Parker's precision manufacturing and corrosion-resistant acetal construction, this adapter delivers a secure, leak-free transition that holds up to everyday residential and light-commercial filtration use, season after season.

Whether you are tying a quick-connect RO manifold into a threaded valve or feeding a tubing run from a threaded filter cap, this stem adapter handles the transition cleanly in a single compact piece. Keep a few in your parts bin and you will always be ready to join push-in and threaded plumbing wherever your project requires it. From new builds to quick repairs, it is the kind of small, versatile component that an installer reaches for again and again on the job.