A simple device that can be inflated/deflated to the required thickness to help strengthen and stabilize your ankles, knees, core and shoulders. The disc has 2 surfaces, 1 with dimples and the other with a smoother, slightly bobbled effect which can aid in massage of the feet. The product includes a pump and can easily be inflated to desired thickness. Dimensions 35cm x 6cm deep (can be increased to over 15cm thick). Please note that you are buying one stability disc (not a pair). Our photograph shows 2 discs in order to illustrate the surface textures of both sides of the disc. We offer the greatest quality products at the lowest prices. If you are looking for superb value on Amazon then look no further than Physique Management!!