A bat for baseball or softball of the present invention includes a first tube having an impact part, a step part and a stopper part, a cylindrical second tube, a fixing component being inserted between the first tube and second tube, the step part having an exterior diameter larger than that of the impact...http://www.google.co.uk/patents/US7993223?utm_source=gb-gplus-sharePatent US7993223 - Bat for baseball or softball
