Luminous LED Quad Wheels are a hybrid indoor/outdoor wheel that uses a magnetic floating spacer to power white LED lights embedded around the tire. All you have to do is roll and the spacers do the rest, lighting your wheels up as you skate! The hybrid nature of these wheels means they're soft enough for the great outdoors, where the LEDs can serve the additional purpose of adding a bit of safety at night (White even glows in the dark!). Our favorite thing to do is to mix and match colors for fun skates at the rink or casual events where you can be on skates - as long as you don't mind being the center of attention! LED Troubleshooting Tip #1: Check to ensure bearings are correctly installed and resting flush against both sides of the magnetic spacer. Even a slightly misaligned bearing may allow the spacer to spin freely with the wheel, which doesn't generate the friction needed to power LEDs. LED Troubleshooting Tip #2: Check the tension on the axle nut. If it's too loose or too tight, it may inhibit the spacer's ability to generate friction (even if your wheel is spinning fine). Make micro-adjustments to the axle nut until you've achieved the desired spin and light-up effect. Specifications Includes (4) Luminous LED Quad Wheels (4) Magnetic Spacers Hardness 85A Height 62mm Width 34mm Weight (per Wheel) 95g