Unions | Conpression | G 1/2 B x 1/2 in. Male National Pipe Thread (MNPT) with 1/4 in. Female National Pipe Thread (FNPT) | Insert Barb x Insert Barb x Insert Barb | MIP Threaded | Socket Weld x Threaded | Socket Weld | Spigot x FIP | Sweat x FIP | Sweat | Threaded MIP | Threaded x Threaded