The 'Tool Plus' unit is used to identify the powered on state of its associated power tool. The 'Tool Plus' is physically clamped to the power cord of the power tool. This power is obtained from either a UL FCC approved AC to DC 5volt USB adaptor, or an associated 'iVAC Pro System' unit.
This unit is great. My shop is only 22 feet by 16 feet and before having this item I would go over turn on the collector the go back over to the saw and then shut down the saw then turn off the collector and this took just a few seconds but it was a pain especially when you are mobility impaired. Now I turn on the saw and then the collector starts up on its own. It was very easy to install and very easy to use. My collector is in its own room with my compressor which I have had wall switches to turn on and off. I would Highly Recommend this item to any one both because of ease of use and ease of setup.