It's built very solidly. Because the tires are thick, there's no side-to-side wobble, allowing for safe training. Roller with Assist Coil: Abdominal rollers train by lifting the body (contracting the muscles), but it's very difficult to lift the body after extending it. The Power Roller Core has an assist coil built into the main unit that supports the lifting of the body, allowing you to steadily train your abs. Two Large Rollers: Equipped with large rollers on the front and back of the main unit. You can extend and lift your body steadily without wobbling side to side, allowing for reciprocal training. Non-Slip Grip: Standard equipment includes a high-quality non-slip grip. It's easy to grip firmly, even if your hands get sweaty. Includes High-Density Mat: Comes with a 10mm thick, extra-thick knee mat. You can train comfortably without hurting your knees. [Body Size]: Width 35.0cm x Depth 24.0cm x Height 15.5cm [Mat Size]: Width 45.0cm x Depth 17.6cm x Thickness 1cm [Weight]: 2kg [Included Items]: Main unit, handlebar, grips x 2, knee mat, instruction manual [Materials] Frame: Nylon, Handle/Knee Mat: Nitrile rubber, Tires: Thermoplastic rubber - Brand: BODY - Color: Blue - Material: Plastic - Accessories: Exercise mat - Function: For abdominal training Thank you for viewing.