These are the new 16mm diameter Ultimate Racing shock absorber membranes compatible with major car brands such as: Mugen, Kyosho, Xray, Serpent, HB, Losi and others.
The material with which they are manufactured and their interior design ensure the membranes retain their original shape and do not deform or crush under pressure. Thanks to this the rebound of the shock absorber remains constant and the performance of the car is much more consistent, even on the bumpiest tracks.