ABEC-9 bearings has now been updated and pre-installed, you just need to replace the wheels. Size: 32mm × 58mm. bearing model:608RS, diameter is 22mm. Tip: don't forget to order 2 sets for roller skates. <br>Product Features: <br>No Batteries Required Luminous Wheels : wheels core motion-powered Light up when they spin.<br> Material：Polyurethane polymer synthetic material<br> Size：32mm x 58mm, Suitable for most skateboards, roller skates, long boards, bearing 608RS. <br> Hardness：82A<br> Quantity：4 Pcs<br> FAST SHIPS<br> Ship by air express and the delivery time is 7-14 working days or faster. :） <br> 1 Package includes: 4 wheels (with magnetic core), 8 bearings (ABEC-9 high speed)<br> ★★★★★100% satisfied and assured. We follow Amazon's policy. If you are not satisfied with the product or dislike the product, you can return it for a refund within 45 days. If you have any questions, please contact me. :)