The KUPO KS-017 Brass 16mm Spigot with 3/8" Male and 1/4" male thread is a universal double-sided, baby 5/8" (16mm) stud with 1/4"-20 male thread on one side and a 3/8"-16 thread on the other. The stud is round and will fit into any 5/8" (16mm) receiver.