Marigold 19-Hole Letter Size Comb Ring Binding Machine Paper Punch Book Binder with Starter Kit - 100 1/4" Black Comb Binding Spines for Office Document Report (Uni-10) Easy to Use -- Achieve professional binding for your documents, proposals, and resources by binding up to 250 pages with the pull of a handle. 2.Industrial Punching Pins -- 19 hardened punching pins allow you to manually punch up to 10 sheets of 20lb letter-size paper at a time. 3.Adjustable Options -- Adjust the punching margins for a perfect fit, ranging from 2mm to 8mm. 4.Bonus Starter Kit -- Start binding right out of the box with 100 -inch black comb binding spines included for free. 5.Lab Tested -- Invest in your office for years to come with the machine that was lab-proven to successfully punch more than 12,000 sheets.