Niteangel Vista Cage Series Supplement Universal Wheel - Only Fit Niteangel Vista Series - hamster cage with Oblique Opening Door, it's not fits for Niteangel Bigger World Hamster Cager Series, please choose it for your cage correctly Simple Installing - Align the grooves between of the cage and universal wheel, and then using the tool that we provide to fasten. The front wheels with lock Safe Cage Wheels - The button of the front wheels designed to ensure security when moving Move Easily - This hamster cage universal wheels can help you move the cage easier Solid & Steady Cage Accessories - The wheels adopted quality beech wood, pet friendly plastic and metal to keep the small pet cage balance and moving flexibly