In 1986, John Middendorf, a Stanford-trained mechanical engineer, founded A5 Adventures. Previously, Middendorf and his companions Steve Bosque and Mike Corbett had nearly died due to portaledge failure during a three-day storm on the 2000 foot South Face of Half Dome, prompting Middendorf to redesign the modern portaledge. A5 portaledges were constructed of highly weatherproof fabrics and engineered to be structurally stable and strong. The company produced three models: the Single, the Alpine Double, and the Cliff Cabana. The A5 portaledges were the first that could withstand the severe weather conditions in remote areas such as the Himalayas and the Karakoram, enabling climbers to expand their horizons to the largest rock faces in the world. Middendorf himself used A5 portaledges on some of the hardest and remote big walls of the world, including during the first ascent of The Grand Voyage on the Great Trango Tower in 1992, the longest vertical big wall (1350m) in the world. The A5 Portaledge was sold worldwide.