These aluminum hinge clamps offer a quick and efficient way to mount a 2.0" OD tube. The connection is made by closing the clamp around the tube and fastening the end with the included 8-32 socket head screw with a 5/32" Allen wrench. The clamp has a mounting hole that fits a 8-32 screw for attachment to a standard 1/2" optical post. We offer a variety of hinge clamp sizes that fit tubes with OD of 0.5 to 2.5".