Retractable dock door safety strap safety strap with sensor safety strap helps keep dock workers safe. Ideal for cross docks and facilities that leave dock doors open. High visibility dock barrier helps workers be aware of loading dock edges. Strap is retractable to keep clear of door opening when not in use. Yellow powder coated steel housing with high strength yellow nylon strap. Spring loaded retractable strap with soft recoil. 15′ l retractable length. 20′ length available, call for details.safety strap with sensor requires use of safety signal (sold separately) to act as a proximity sensor that detects when the strap is engaged. this item is specifically for a visual deterrent and does not satisfy osha 1910.21 subpart d working walking surfaces standard