Swingline GBC 2515700 ProClick Pronto Spine Cassettes, 5/16" Dia., 40 Sheet Capacity, Black (Box of 100) PROFESSIONAL PROCLICK  Choose the reliability and ease of a ProClick binding. Dependable black binding allows you to open and edit the contents without use of a machine. CONVENIENT CASSETTES  Pre-loaded cassettes of 20 spines each. Handy cassettes are designed for frequent binding. High capacity cassettes are ideal for use in busy print shops and corporate offices. 40-SHEET BINDING CAPACITY  Each 5/16 diameter spine securely binds up to 40 sheets. Neat spines are perfect for smaller projects. EASILY EDITABLE  Enjoy the flexibility of proprietary ProClick technology. The sturdy binding spine simply zips open and closed. Use your finger or a pen to open it - no need for a machine. EXCLUSIVE COMPATIBILITY  ProClick cassettes are designed exclusively for use with the highly productive, automated GBC ProClick P2000 and ProClick Pronto P3000 binding machines (sold separately). 100 SPINES PER BOX  With 20 spines per cassette and five cassettes per box, these spines are sure to accommodate any big project, pronto. Ideal for professional print shops and corporate offices.