SUPERIOR BOAT AND MARINA PROTECTION: The Marinaquip Docking Wheel cannot deflate, go flat or puncture. The massive 75mm (3”) axle means it never needs greasing or any maintenance and will remain free moving for its lifetime. The bracket is fastened on two planes and is incredibly strong and resilient being constructed from heavy duty marine grade 316 Stainless Steel in 6mm (1/4”) plate.