Brocraft Boat Launching Wheels / Boat Launching Dolly with 12 Inch Wheels Constructed of marine grade aluminum square tube with CNC processing Weight Capacity: 400lbs Pressurized wheels; 12" in diameter. Wheels easily lock up when not in use and easily fold down for boat moving Push the stainless steel solid button to operate, Auto lock wheel arm system by Easy Sliding Transom BracketPush the stainless steel solid button to operate, Auto lock wheel arm system by Easy Sliding Transom Bracket Includes two years warranty