I have two Airtech vacuum HP200V dry piston pumps for sale. They are rated at 27.75 Hg (at the pump) and cost $875.00 each new. I have them working in tandem on 300 taps and in the woods and I have between 18 and 22 Hg of vacuum. They are very simple to use and are great for small operations up to 500 taps. Both together - $875.00 For just one - $500.00 I use them with a mechanical releasor by plumbing it into a small 11 gallon air tank. (included with pumps)