SharkBite 1/2-in PEX Barb x 3/8-in OD Compression Brass Quarter Turn Stop Straight Valve (4-Pack)The SharkBite 1 2 in. Barb x 3 8 in. OD Compression Straight Stop Quarter Turn Valve controls water flow to household plumbing fixtures. The Straight Stop Valve is used where the water pipe enters the room to allow for easy shut off of water flow to the end fixture allowing for maintenance and repair without having to turn water off to the entire home. The SharkBite 1 2 in. Barb End can be connected to PEX Pipe using Copper Crimp Rings or Stainless