These rings slips over the front wheels of the walker allowing the front to slide, making it handle like a shopping cart. It takes a fair bit of force to get them on, so they shouldn't slip off. Upscale a few percent and reprint if they don't go on at all. Reminder: Print out of a material and color that wont mark the floor(pictured is clear PETG). Warning: These will make the cart less stable and unsuitable as a walker. Do not use these if your child uses the cart for stability! Only use these if your child wants to use it as a cart for transporting things. I accept no responsibility for you modifying your property.