LOOP-LOC introduces a better way to install its safety covers on large commercial pools and pools with rails and other non-removable raised obstructions – the patent-pending new AQUA-LOC treatment. (1) YKK industrial zipper secures cover sections. (2) Black urethane UV coating protects zipper. (3) Stainless steel block prevents zipper from being opened. (4) Key-lockable cable secures block in place. It’s easy to install, easy to use, and greatly reduces the need for multiple sections and strap-and-buckle treatments. Meets all ASTM standards for safety covers.