Mead CombBind Binding Spines - 0.31in Maximum Capacity - 40 x Sheet Capacity - For Letter 8 1/2in x 11in Sheet - Plastic - 125 / Box

5/16in spine accommodates up to 40 letter-size sheets For use with any comb-style binding machine (sold separately) Permanent design allows pages to stay flat for easy manageability Sturdy material resists damage for long-lasting use