About this product: 【Fully Fabric-Covered, Silent Design】?? High-density fabric completely blocks the sound of the springs. Allows for training even late at night in apartments. 【Lumbar Protection, Flexible Frame】?? Supple material absorbs impact to the lower back. Does not injure internal organs even with prolonged rotation. 【High Load with Reinforced Springs】?? Thick built-in springs provide 1.5 times the normal load. Burn more calories in the same amount of time. 【Multi-functional Convertible System】?? Provides a variety of training options, from yoga warm-ups to fat burning, all in one machine.