a Holds objects from 2 3/4" to 3 1/4" (70mm to 83mm) in diameter. a Each clamp supports a safe working load of 50lbs (23 Kilos). a Mounts easily with one 1/4" (6mm) bolt or screw. a Mounting area: 4 1/2" x 1 1/4" (113mm x 32mm).