Economy style spine clamp or book clamp for paper cutter back gauge. Sometimes called book trimming guides these book clamps keep books and other stapled or stitched booklets flat for accurate and square cutting. They are very effective at assuring an even cut by holding down the spine of a book. The book clamps install on the guillotine paper cutter back gauge by tightening them to the back gauge ribs. They are made of cast bronze and are usually installed in pairs. PRICE IS PER PAIR