These skates have built-in components that make the wheels light up, and they will glow semi-permanently unless the wheels wear out. They are not battery-powered, so there's no need to worry about battery replacement. You can see them glow beautifully in the dark! 【For Beginners】Double roller skates significantly increase stability, making them easier for beginners to try. They are perfect to give as a gift. 【4 Size Adjustable】These roller skates are available in sizes S and M. Adjustable roller skates are the perfect gift for those who are still growing. Sizes: S 18.5-21.3cm, M 21.5-24.5cm. Materials: Upper: Mesh, PU / Lining: Sponge / Support: Aluminum Alloy / Rollers: PU 【Durable and Smooth】The inline skate frame is made of reinforced aluminum alloy, and the high-rebound 82A polyurethane wheels are wear-resistant, providing a smoother and faster ride. The silent ABEC-7 bearings are made of premium quality carbon steel. 【No Tools Required】With one button, you can change the size in 4 stages at 0.6cm intervals. Choose from two sizes, 18.5-24.5cm, and enjoy with the family!