Bonzer Can Opener wheels are available in 25mm and 40mm sizes. The 25mm wheel should be used in the Bonzer Classic R and Bonzer EZ20 can openers. The 40mm wheel should be used in the Bonzer EZ40, EZ60 and Titan. Using the wrong wheel in the wrong can opener will not work. Overtime can opener wheels and blades will wear out. Replacing them will give a new more efficient feel to the can opener.