As this product is suitable for old type ball head shower arms, the old type thread size is used Made from copper, corrosions and rust resistant for durability 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, Manufacturer: Shurhome