Sterling invented the sew bound loop prusik over 16 years ago as an innovative answer to bulky knots. Their RIT 8 mm and 9 mm Bound Loop Prusiks are the latest extension of that product line and offer arborists durable, versatile tools for rigging, climbing and lanyard adjustment. The RIT Ring Prusik is a versatile tool for rigging, climbing and lanyard adjustment. Made with Sterling' s durable RIT 500 construction with a Twaron sheath and nylon core for heat resistance and durability.