Mead CombBind Binding Spines - 0.37in Maximum Capacity - 55 x Sheet Capacity - For Letter 8 1/2in x 11in Sheet - Plastic - 125 / Box

3/8in spine accommodates up to 55 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