PDP Concept Cymbal Boom Arm 9" Tube Concept Cymbal Boom Arm with 9" Tube This Cymbal Boom Arm by Drum Workshop a 9" by 3/4" boom arm extension that helps percussionists maximize their boom stands This Cymbal Boom Arm by Drum Workshop a 9" by 3/4" boom arm extension that helps percussionists maximize their boom stands