... " ,25mm diameter,1.5mm thick Aluminum tube,4 steps. Aluminum RV Bunk Ladder, 60" ,25mm diameter,1.5mm thick Aluminum tube ... from dropping, sliding or rotating. This motor home, travel trailer or RV bunk ladder is made from aluminum alloy and supports up ... choice of hook and retainer 'Docking System', or 1" hook. trailer bunk ladder