Check the listing for details. HEELYS Fats 5 Replacement Wheel, Black. Condition: New with tags. Listed at 19.00 USD. If you look inside the empty wheel cavity (the wheel cavity is the hole on the bottom of the shoe where you normally insert your wheel and/or plugs), you'll find the type and size of wheel/plug that your shoe uses imprinted inside the wheel cavity. For example, if it reads 'FATS-L (US 9-12)', you will need to order FATS wheels and/or plugs in a size LARGE, which fits shoes in US sizes 9 through 12. Please note: If the imprint only shows a size (Small, Medium or Large), you will need the FATS style in the stated size. ShoeCo.Shoes HEELYS Fats 5 Replacement Wheel $ If you look inside the empty wheel cavity (the wheel cavity is the hole on the bottom of the shoe where you normally insert your wheel and/or plugs), you'll find the type and size of wheel/plug that your shoe uses imprinted inside the wheel cavity. For example, if it reads 'FATS-L (US 9-12)', you will need to order FATS wheels and/or plugs in a size LARGE, which fits shoes in US sizes 9 through 12. Please note: If the imprint only shows a size (Small, Medium or Large), you will need the FATS style in the stated size.