The Stainless Steel Reducer Bushing from Really Right Stuff serves as a an adapter when thread sizes don't coincide with each other. For example, certain tripod heads will not attach because the threaded slot is larger than the tripod mount, so the bushing reduces the 3/8"-16 thread down to a 1/4"-20 size allowing the head to attach. Because of the flathead screwdriver slot, the bushing can be easily removed to convert the mounting thread to its original size.
UPC: 818413028418