A21 DEREK RODDY SIGNATURE EDITION WITH ELECTRONIC KIT [DR-A21] Footboard for Derek. Incised lettering AXIS and USA. Laser 21 and Autograph. Black or Silver. We would like to thank Derek Roddy for his participation in the development of the A21. The most immediate, direct response. 21 degree power forward angle accelerates the beater into the bass drum with greater force and velocity.