The AW & AWH versions are recommended for use right underneath most HVAC equipment As well as in conjunction with structural metal bases and concrete inertia blocks. Baseplates of all designs are factory drilled to accomodate safe and efficient installation of the spring mount into the composition or flooring. -OtherHVAC https://antivibrationspringmount36812.buyoutblog.com/39143071/seismic-vibration-isolators-for-dummies