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