These Sealed-Blok self retracting lifelines (SRL?) incorporate a patented concept that separates all dynamic components, including the motor spring and brake, from foreign elements such as grease, moisture and dirt. You can always trust your SRL to work at peak efficiency without worrying about the environment you're working in. Our sealed SRLs are backed by decades of PRO en field service for absolute confidence, safety and reliability. An SRL? 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 will activate Stop ing the fall and reducing the forces imposed on the user to safe levels.