Half Size Mini 3-Ring Binder Mechanisms - Metal Spine Piece Only | SpiralBinding
Choosing Between an O-Ring and a D-Ring Binder - SBDPro Blog
Amazon.com : ½ Inch 3 Ring Binder .5 inch Black Clear View Cover with 2 Inside Pockets, Colored School Supplies Office and Home Binders, 6 Pack – by Enday : Office Products
Wall Mounted Hanging Ring Binder - 1" O Ring (3 Ring)
Case•it Mighty Zip Tab 3" O-Ring Binder with Expanding File Folder, Black, assembled product height 13.11" X 12.75" W X 3.74" L - Walmart.com
Pen+Gear 3-Ring Poly Standard Binder, 1" O-Rings, Black - Walmart.com
Blue Summit Supplies 1" Mini Binder, O-Ring, White, 6 Pack
Amazon.com : Mr. Pen- Binder Rings, Loose Leaf Binder Ring, 36pc, Assorted Sizes, Book Binder Rings, Ring Binder Clips, Metal Rings for Index Cards, Rings for Flash Cards, Index Card Rings, Book