An apparatus for reducing non-uniform stretch of a belt used in the CMP system is disclosed. The invention also proposes that a component that generates a magnetic field, and spaced apart from it, a magnetically sensitive element be disposed in the vicinity of the recess. The paddle includes waveguides for guiding radio waves between an antenna of the paddle and an antenna or the receptacle. The opening is adapted to enable the pressurized gas to escape from the hollow portion of the body, such that the escaping gas provides energy to an associated object operatively associated with the body. Then, the entire cap is heated and heat-shrunk at a predetermined temperature and the thermosetting waterproofing agent is heat-hardened.