The AW & AWH types are recommended to be used instantly under most HVAC equipment and in conjunction with structural metal bases and concrete inertia blocks. Baseplates of all models are factory drilled to accomodate safe and efficient installation of the spring mount to the composition or flooring. -OtherHVAC Equipment: https://seismic-spring-isolators65999.blog5.net/88056133/the-smart-trick-of-anti-vibration-solutions-that-no-one-is-discussing