The Generac Generator Power Transfer System Load Manager Model 01403-0 is a manual transfer switch designed for use with Generac (or other brand) generators. This system allows for seamless power transfer between the generator and the connected load, ensuring a reliable and efficient power supply during emergencies or power outages. The load manager feature helps manage the connected devices and appliances for optimal performance. I bought these brand new (I have 2) a few years back for a cabin project and never used. $125 ea or a bit less if you buy both. No box or manual, probably can find one on the net or from Generac but frankly pretty simple for anyone with moderate understanding of electrical to figure out. Basically gives you the option to choose between line power and generator with the flip of a switch and choose to energize 1 x 220v circuit and 4 x 115v circuits individually and has two watt meters to monitor usage. I am near the corner of Cave Creek and Carefree Highway.