3M™ DBI-SALA® Nano-Lok™ Extended Length Self-Retracting Lifelines (SRL’s) are designed with your workforce in mind. We're advancing the versatility of 3M™ DBI-SALA® Nano-Lok™ SRLs; available in 9ft., 11ft., 15ft., and now 20ft. Lengths. The family of Nano-Lok SRLs combines fall protection with ease-of-use and comfort for multiple applications. 3M™ DBI-SALA® Nano-Lok™ Extended Length Self-Retracting Lifelines (SRL’s) are rugged, yet lightweight and carefully engineered devices you can count on for comfortable and efficient fall protection. Stainless steel components, an anti-ratcheting brake system and a semi-sealed design help provide the user with a system built to last. Our SRLs are backed by decades of proven field service for reliable fall protection. This SRL is designed so that the lifeline will extend as the user moves away, and retract automatically enabling the user to move about within a recommended working area at normal speeds. Should a fall occur, a speed sensing brake system activates, stopping the fall and reducing the forces imposed on the user.