BEESCLOVER 1/4" Male to 1/4" Male Threaded Screw Adapter (2-pack) approx.diameter:16mm 2 pieces pack. 2 Precision made 1/4" to 1/4" Stainless Steel (metal) screws,Easy to use. approx.Total length:20mm This is a universal adapter spigot stud for the studio use .