Kong Duck Rope Clamp/ascender Black. Due to the small dimensions it can be easily inserted even with only one hand. The big hole allows the rotation of sleeve connectors. The Duck is borne like an emergency belay device during retrieval self-belay and progression maneuvers and for regulation of daisy chains. Specifications for Kong Duck Rope Clamp: Manufacturer: Kong Color: Black Fabric/Material: Aluminum Weight: 2.5 oz Package Contents: Kong Duck Rope Clamp The Kong Duck Rope Clamp is a quality addition to the Kong lineup. For more great deals on Pulleys & Ascenders by Kong please browse our Kong Ascenders & Descenders page.