As this product is suitable for old type ball head shower arms, the old type thread size is used : Simply screw the adapter onto the end of the shower arm to convert to a standard 1 / 2inch male thread This adapter is for ball end shower arms only Converts ball end to 1 / 2inch male pipe threads The shower arm adapter is threaded and fitted with a rubber gasket to ensuring a secure, none leak connection Made from copper, and rust resistant for durability, Manufacturer: Greabuy