Patent ID: 7335118

Claim:
A device mountable in a tennis racket, comprising: a hollow cylindrical cushioning member including an annular groove, a central chamber, an axial channel crossed the chamber, and two recesses at both ends of the cushioning member; and a rigid, doughnut-shaped, hollow sound producing member mounted in the chamber and including an enclosed space and an axial tunnel therethrough, the tunnel being communication with both ends of the channel, wherein three straight wires of a network of the tennis racket pass three sides of the groove for fastening the device in an open space of the network such that the device is adapted to absorb reaction when a ball is hit by the tennis racket; and wherein the strength of sound produced by the device is determined by whether air flowing through one recess, one end of the channel, and the tunnel co-acts with air in the space of the sound producing member to produce resonance or not by whether a handle of the tennis racket held by the hand of a tennis player correctly hits the ball or not.