This Primaflow Brass Hexagon Threaded Bush is designed for reducing thread diameter in plumbing fittings. It features 1 1/4" x 1" BSP threads, which actually measure 1 1/2" and 1 1/4" in diameter respectively. For best results, use PTFE tape or thread jointing compound to ensure a watertight or gas-tight seal. This product is part of the Primaflow Threaded Brass Fittings range. Weight: 0.13 pounds.