Self-retracting lifelines, or SRLs, connect a worker's full-body safety harness to an anchor point on a building or structure to stop the worker from free-falling and help prevent injuries in the event of a fall. They attach to a D-ring on the safety harness and extend and retract as the worker moves, allowing him or her to move freely. If the worker starts to fall, the SRL will brake suddenly to stop the fall and absorb its energy. SRLs allow the worker to move farther away from the anchor point than would be possible with a shock-absorbing lanyard. SRLs typically stop a fall within 2 to 4 ft. and require less fall clearance than shock-absorbing lanyards. Self-retracting lifelines are commonly used by people working at heights in the construction, manufacturing, welding, utilities, transportation, and oil and gas industries.