With three off-road AIR Tent Trailers (the OP2, OP4 and OP LITE) and one hard-sided Hybrid Travel Trailer (the OP15), each OPUS comes loaded with an axle-less trailing arm independent suspension with shock absorbers, galvanized steel chassis, an articulating hitch, mud-tires, spares and front rock guard as standard to tackle the roughest of terrains with ease.