Heil Sound SM-2 Shockmount for PR-30 and PR-40 Champagne SM-2 is designed for use for both the PR 30 and PR 40. The SM-2 Shock Mount is a flexible support system that helps repress low-frequency rumble on the microphone line by absorbing and damping vibrations picked up from the studio desk or console The SM-2 mount is designed for use with the large-diameter professional-grade Heil Sound microphones, including the PR 30 and PR 40 Its 5/8" threads mount onto the PL-2T "Topless" and other mounts for easy installation The SM-2 Shock Mount is a flexible support system that helps repress low-frequency rumble on the microphone line by absorbing and damping vibrations picked up from the studio desk or console