SP structure Patent No. 43312680 Patent No. US8,505,334,B2

 By using a single piece of rubber in a spiral shape, the force is dispersed and a perfect fit is achieved. Even with a large design, it is supported by two pieces, so it is stable and does not feel swaying.

If the rubber becomes dirty or stretchedFrom hereCan be exchanged. Exchanges are free, but the customer is responsible for shipping costs. The replacement period is 2 years.