The Otter Pro Sleds feature a Roto-Molded construction for the ultimate in strength and durability. With seamless surfaces and uniform thickness across the board Otter has produced one of the most durable sleds ever built. The processes used to manufacturer their ice sled have to meet strict tolerances and must distribute more material to help absorb the shock and stress where the sled gets it the most. The Otter Pro Sled has a raised back to help increase the cargo security to prevent items from falling out during travel behind a snowmobile or ATV. The outer lip has been reinforced for strength and support to hold ties and rope better and creating extreme sidewall stability.