In 1972 the climber brothers Gregg and Jeff Lowe designed the LURP, a highly innovative portaledge prototype. The design's collapsible frame allowed the Lowes to climb without the bulk of a cot. Every significant portaledge since the LURP has had a collapsible frame. Another pioneering feature of this design was its nylon fly tent, which provided an enclosed shelter from the elements. Fly tents quickly became a standard element of portaledges. Jeff Lowe used the LURP on the first winter ascent of Yosemite's Half Dome. Although the prototype was never sold to others, the brothers included it in their catalogue of climbing products, which circulated widely among climbers.