Please make sure to carefully confirm the specifications and size of the product before purchasing to ensure it is suitable for your mobility aid. This will prevent the purchase of the wrong product and ensure a better experience for you! High strength:In order to increase strength and extend service life, this product uses 12.9 grade high-strength screws. With high-quality casters and metal ball bearings, these replacement wheels are built to last. The ABS wheels have a strong load-bearing capacity, making them perfect for wheelchair assist devices and rollators. Anti-skid and wear-resistant: The PU environmentally friendly replacement tires are thickened and anti-skid, making them suitable for use on all surfaces, both indoor and outdoor. They are also wear-resistant, ensuring your wheels will last for a long time.