Pipe Plug Socket Set The new 3/8" Drive Pipe Plug Socket Set from Grey Pneumatic (1211P) contains male socket sizes from 3/16" to 3/8" and female sizes from 1/4" to 3/8", which are useful for removing differential fill plugs, transmission plugs and a variety of other specialty uses. These sockets are made from impact grade material for added durability and the entire set comes packaged in a molded case with sizes molded for easier identification and storage.