Cymbal Boom Arm 18in. Model #SPC20 This Cymbal Boom Arm from Sound Percussion Labs features an 18″ down tube with a 7/8″ diameter and a 12.7mm knurled hideaway boom with ratchet tilter. Shop now at the following retailers: PRODUCTS All-In-One SetsShell PacksSnare DrumsMarchingConcertPercussionVelocity Hardware ACCESSORIES Stands & Pedals Drum Practice Pads & Practice Mutes Bass Drum Impact Pads Replacement Parts Cymbal Holders & Arms Percussion Mounts & Stands Clamps Drum Keys Drumsticks SUPPORT Customer SupportFAQsManualsWarrantyPrivacy Policy FollowFollowFollow