Large gear driven 4.47:1 60,000 RPM limit supercharger. I think this is a aircraft supercharger made by Rayjay/Rajay. The tag has been removed. Mach II is cast into the housing. It is in new condition. No brackets or pulleys. it requires engine oil for lubrication. I was going to use this on my 393 but I am going another direction. PM me with your email address for pics. $575 Shipped anywhere in the US.