These wheels can be used to replace the original wheels of Spaza 250/350. (PU abrasion-resistant inline skate replacement wheels, 76mm) Bearings are not included, so please purchase those with an inner diameter of 8mm, an outer diameter of 22mm, and a thickness of 7mm online or elsewhere. Two bearings are required per wheel. (Stainless steel is recommended) The caster axles will fit smoothly if you lightly sand them with sandpaper. They do not interfere with the cooler box itself, and the wheels do not touch the ground when the cooler is placed flat. Thank you for your consideration.