Two attachment methods for ultimate versatility - loop system and fixed end system Sturdy, durable plastic Lightweight, strong construction The CamJam Cord Tightener features the strong plastic body of a carabiner combined with a locking cam mechanism for a knot-free way to tighten, tension, and secure light loads. The CamJam can be clipped to fixed anchor points and the cam mechanism will lock cord in place with the desired amount of tension. Fits rope sizes: 1/16'' - 3/16'' | 2mm - 5mm.