Get the best of both worlds with convenient ProClick spines! Easy to use spines give you a professional presentation with an attractive black plastic spine, but are also easy to open for flexible editing and rearranging. Binding spines securely bind documents and let pages lie flat for 360° rotation. Spines zip open and closed to make adding or removing pages simple. Ideal for use with GBC® ProClick binding machines and pre-punched paper. Sheet Capacity: 45; Spine Diameter: 5/16"; Number of Rings: 32; Color(s): Black.