Description: The shell is made of propylene and the wheel is made of PVC.With extra long and thick steel pipe for durability, safety, and nice load capacity. It will not make any noise because of the tire pattern.Ensure safety and comfort. Not damage carpet or floor at all. ABs roller helping you to burn calories, build muscle and improve your overall endurance.Two and four wheels are both perfectly to choose. This ABs roller equipped with extra thick sponge handles to minimize hand fatigue while maximizing grip comfort and controlling.Our ABs roller equipped with extra thick knee mat to keep your knee safe maximize. The Ab wheel roller is lightweight and portable, which is easy to assemble and easy to use. Specification: Model Number: Two/four wheels Color name: Black Function: Belly Shell material: propylene Wheel material: PVC Size Chart: 2 wheels:Sizeapprox 42x17cm/16.5x6.7inch; Weight: approx 1kg 4 wheels:Sizeapprox 50x15cm/19.7x5.9inch; Weight: approx 1.4kg Package Includes: 1 piece ABs roller;1 piece knee pad : Notes: Please allow slightly difference due to manual measurement . Colour may be slightly different since different monitor.Thanks.