Wheel material:Plastic This AB ROLLER is designed to work and build the abdominal muscles. Has dual wheels for stability and non-slip handles for comfort. The compact size allows you to store it anywhere or carry it when travelling. Include a knee pad for you to protect your knee Size: As the picture shows Quantity: 1 Pc Note: Due to the difference between different monitors， the picture may not reflect the actual colorof the item. Thank you! Color: we send it random Package includes: 1 x Ab Abdominal Roller Wheel 1 x Knee Pad If you satisfied with it， please give 5 star.If you feel your shopping experience with us was anything less than FIVE STAR ， Please contact us immediately! We will give you a satisfactory answer.