Spine cassettes are compatible with GBC ProClick Pronto P3000. Easy to edit. Zip open & closed so you can swap pages in & out quickly anywhere, anytime. Spine cassettes help deliver great professional-looking presentations. Using spine cassettes gives documents a unique, contemporary look. Pages lie flat & are held securely in place. Each cassette holds 20 spines. ProClick editing zip tool is sold separately. Spine cassettes are made with a high percentage of recycled material.