Conceived for single ropes with a diameter between 8 and 13 mm, Duck is the first and only clamp that also works on flat and tubular slings from 10 to 15 mm width (even if these are not certified for progression). Due to its small dimensions, it can be easily attached with one hand.The big hole allows locking connectors to rotate. Duck was born as an emergency rope clamp for retrieval, progression maneuvers and for the regulation of daisy chains.FEATURES: Aluminum Tested to EN 567 Standards Works with 8mm - 13mm rope Weight: 2oz Assorted Colors. Color is NOT guaranteed *The Kong Duck IS NOT TO BE USED as a fall arrest device. *NEVER have slack in any rope when using a Kong Duck.