The sit-up bars are mainly made of high quality metal materials, which are sturdy and durable. Great support for waist, abdomen, legs, body sculpting, lifting and muscle building. Upgrade support bar, thickened rubber suction cup and foam, make exercise more safe and comfortable four height modes for you to choose according to the practical situation. Press the spring buckle to adjust the height. Thick, soft foam grips are comfortable against your feet and prevent chafing. Height adjustable to meet different needs. The fitness machine is compact and very convenient for storage and transport wherever you go. Suitable for smooth surfaces such as tiles, marble, hardwood floors wood, please keep the floor and the suction cups clean. press the black button up or down to release/fix the suction cup.after wiping the floor with a damp cloth, the suction power may be further strengthened.