TruRev"s Helius: 110mm wheel Introducing one of the most innovative wheels under the sun. Embody the strength, might and power of Helius: High Rebound, Low Density New Carbon Nanotube Material Structurally uses a Z-axis Design.Durometer: 86A Weight: 142 Grams Z-axis Design / Tower Effect The Z-axis structure absorbs shock and provides the amazing rebound and grip with maximum roll. NOTE: For instructions on how to replace your Ripstik wheels please visit Youtube "Replace Ripstik Wheels" for a step to step guide.