I agree with James S. Looking around it appears from their site (and others) that it is a low volume vacuum pump where you run hoses to get the last drop. I found some of their images
amusing (before - looks like the pump is turned off, after - looks like the bilge
It would seem this is fairly easy to setup on your own, but a nice self contained unit has its advantages. If however the "last half inch" is the issue, maybe adding a diaphragm
pump to assist the standard would be a better answer.