The DynamO is a hole-cutting template for resonant Bass drumheads that provides a vent hole for all drum mics. The DynamO is a laminated Mylar ring with a high-strength adhesive backing, providing added durability for the drumhead to prevent tearing when adding or removing microphones. Product Features: High strength adhesive backing Provides vent hole for all Drum Mics Provides added durability to the vent hole when using bass drum microphones Resonant drumhead hole cutting template