Zip Combs SpinesConvenient Zip Combs spines allow you to easily edit bound documents without a machine. Simply open spine with a pen. Make your changes and snap spine close. Upgrade your CombBind documents easily for better functionality and a more professional appearance. Zip Combs spines work on any CombBind punched paper (19 holes). Sheet Capacity: 110; Spine Diameter: 5/8"; Number of Rings: 19.