This Double End Spigot with 1/4"-20 and 3/8" Male Threads from Impact has a universal 5/8" (16mm) diameter and features both 1/4"-20 and 3/8" male thread sizes.
Thread Size
1/4"-20 male 3/8" male
Diameter
5/8" (16 mm)
Impact
Double Ended Spigot with 1/4"-20 and 3/8" Male Threads