The four upper truss fasteners are made from Baltic Birch plywood with easy quick-release cam levers and stainless steel hardware. These fasteners attach two poles together, allowing for reduced setup time. The mounting block is slotted, which allows you to set the cage on the fastener and clamp it tight. The cam lever is black anodized aluminum. These fasteners will accommodate 0.75", 1" or 1.25" tubing (please specify). For use on telescopes up to 22". Greater accuracy than clamps, set of four.