I have purchased the Ultra-Lube 2000 device for use at our plant. We are just providing training on it now. The specifications on the device are included at the website www.UVLM.com. The use of the acoustic device is quite subjective. There are some guns that have scales to measure the sounds coming from the bearings. I have encountered some resistance from the crews but that happens with every change. We may look into hooking the device up to a scope to get a more objective reading from the sounds. The specs that we have state that the frequency range is 20Hz to 20 kHz.