Guardian Halo Big Block Cable Retractable Lifeline - 50 ft.* The Halo Big Block Retractable features corrosion resistant stainless steel and aluminum components to extend the life of this well built retractable. * A dual braking mechanism makes sure that your retractable lifeline stops when it's supposed to. * A common complaint among construction workers, the Halo Big Block reduces nuisance lock up so you can spend more time focusing on the task at hand. * Guardian Fall Protection's Halo Big Block is lighter