These 3/4” binding spirals are a great way to bind documents, reports, presentations, and more. They are made of durable black plastic and have a 48-ring design that can hold up to 170 sheets of paper. The spirals are 12 inches long and 3/4 inch in diameter, so they are perfect for standard letter-sized paper or smaller. Features: - Pack of 5 spirals - 12 inches long - 3/4 inch diameter - 48 rings - Black plastic - Can hold up to 170 sheets of paper - Durable construction - Easy to us. Benefits: - Professional-looking binding - Lay-flat design - Securely holds pages together Uses: - Binding documents - Reports - Presentations - Workbooks - Manuals And more! Here is a guide to help you decide which spiral you need for your print: Paper thickness by lbs: 20lb Paper = .0038” per sheet 24lb Paper = .0048” per sheet 28lb Paper = .0058” per sheet 32lb Paper = .0062” per sheet For double sided printing - Divide your page count in half and multiply that number by the measurement for the paper your using above. For single sided printing - Multiply you page count by the measurement above for the paper you will be using. If you already have you print - Measure the stack of sheets to make sure it will fit into the spiral size. Spiral size maximum paper stack size fit: 1” Spiral = upto 13/16” stack ¾” Spiral = upto 11/16” stack ⅝” Spiral = upto 9/16” stack 9/16” Spiral = upto 15/32” stack