The VN 2000 series bill acceptor is widely known as the best validator on the market.
The VN-2521 is most commonly used in cold food vending machines.
This unit is what’s known as a “flashport” model, which means it can be upgraded using a simple hand held programmer for any new currency updates that come out.
These validators have already been upgraded to the latest currency versions, including the 2008 $5 bill.