The material is made of a very soft foam, coupled with a very good suspension for optimal training. This little thigh muscle machine works Foam protection handle, outer layer up to 30mm, comfortable grip, strong sweat absorption, increased friction and increased safety. Thanks to its thick high-density steel, the spring does not deform, so it can withstand more weight, is durable and resists dirt and drops. The springs do not make any annoying noise, which makes training very pleasant. Compact design: lightweight and portable, comfortable to use and easy to store. S-shaped design, good elasticity and strong resistance, long-term use of this product can slim your legs and reduce thigh fat. You can take this training device and the use almost anywhere, like on your lunch break at the office. The exercises are well explained and easy to perform. Exercise as soon as you wake up. very convenient. The training manual is very practical and detailed.