Swingline GBC ProClick Pronto Spine Cassettes, 5/16 inch Dia., 40 Sheet Capacity, Black, 100/BoxFor use with P3000 only. Preloaded cassettes mean fast production—eliminates loading individual spines. Provides upscale look and feel. ProClick lets pages lie flat with 360 degree rotation for convenient note taking and photocopying, and it lets you easily add and remove sheets with a special editing tool. Won't scratch, chip, peel or discolor. Sheet Capacity: 40; Spine Diameter: 5/16"; Number of Rings: 32; Color(s): Black.