The AW & AWH models are recommended for use specifically under most HVAC equipment and in conjunction with structural steel bases and concrete inertia blocks. Every single spring can travel for a minimum of 50 percent much more than the rated load in advance of it may be totally shut. https://open-spring-vibration-iso57912.ivasdesign.com/60285976/spring-vibration-mounts-for-hvac-for-dummies