3/8″ x 1/2″, sharkbite push fitting x fnpt adapter, makes a connection to 3/8″ pipe using a push fit connection & then gives you a 1/2″ female npt adapter on the opposite end, use to join copper, cpvc or pex pipe in any combination with no soldering, clamps, unions or glue, just insert the pipe & the stainless steel teeth bite down & grip tight, while a specially formulated o-ring compresses to create a perfect seal, disassembly is just as fast using the simple disconnect tool, can even be rotated after assembly for easier installation in tight spaces, certified for potable water supply & hydronic heating applications.