Mead CombBind Binding Spines - 0.31" Maximum Capacity - 40 x Sheet Capacity - For Letter 8 1/2" x 11" Sheet - Plastic - 125 / Box | Bundle of 5

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