Brass Craft CR3901L R1 1/2-Inch Nom Comp by 1/2-Inch O.D. Comp by 3/8-Inch O.D. Comp Left Brass Craft CR3901L R1 Dual Outlet Stop, Rough Brass Stop type: compression inlet Riser outlet: 1/2-Inch OD (3/8-Inch nominal) Inlet: 1/2-Inch nominal copper (angle) Left-side outlet: 3/8-Inch OD (1/4-Inch nominal) 1/4-turn on/off provides smooth operation