Bought this on ebay from a screen printing supply shop. Hadn't really seen one before and was used to using a t- square. Tell the truth this is way easier. It has a lip that goes over the side of the pallet. They make them for 15" and 16" wides. I bought a 16" and put a vinyl strip at 15" so we only need one (cheap-ass).
Works great on the auto because of the tighter space.