SUNWAYFOTO brand Arca-Swiss compatible Subtend Clamp DDT-53. Precisely engineered / exact Arca Standard. Under and over independent Arca clamps. Use it with 2 long plates or rails for precise dual control. Length: 54mm. Width (inc handles): 109mm. Height: 22mm. Weight: 158g. All metal construction. Metal knobs with no rubber or plastic. 3/8"-16 threaded mounting hole. Includes Stainless steel 1/4"-20 bushing adapter. Compatible with all Arca Swiss plates.