Check the listing for details. Kelly Concepts Kelly SHU FLATZ System for Sennheiser E901 (2-pack) Bundle. Condition: New. Listed at 94.00 USD. For decades, engineers have placed boundary microphones inside of kick drums. These mics yield a full sound with extended bandwidth and copious apparent volume, especially when used in conjunction with a good dynamic mic. Unfortunately, keeping a boundary mic from bouncing around inside the drum has always been a challenge. The Kelly Concepts Kelly Shu Flatz System solves this age-old dilemma. Made from 30% fiberglass and high-density nylon, this innovative shockmount holds your Sennheiser e901 microphone firmly in position utilizing pre-existing hardware - no drilling required. Installing the Kelly Shu Flatz System is as easy as removing and replacing four screws. Both onstage and in the studio, the engineers at Sweetwater love the Kelly Concepts Kelly Shu Flatz System!.