GBC CombBind Binding Spines, 0.25-Inch, 25-Sheet Capacity, Navy Blue, 100 per Box (4010485)
19-ring plastic spines won't scratch, chip, peel or discolor. Bind 11 x 8-1/2 documents. Editing capability with a machine. Compatible with GBC and other plastic comb binding machines. To select correct diameter, measure thickness of material (including covers) and add 1/8". Binding Spine Type: Comb, Global Product Type: Binding Spines, Sheet Capacity: 25, Spine Diameter: 1/4 in.