Cardinal Easy Open Locking Round Ring Binder, 8.5 x 11 Inches, 1-Inch Capacity, Black (18812) for $2.55

EasyOpen® locking round ring mechanism instantly engages when closed, eliminating two-step and two-hand operation. No scratched desks or bookshelves from triggers that don't close up. Opens and closes with just the touch of one finger. Safer and easier to use than other metal ring binders--no more pinched fingers.