Letter size ring binder mechanisms are the metal spine pieces from binders. These binder parts (binder spines) pieces are available in 3-ring for letter size 8.5" x 11" papers in ring sizes from 1/2" up to 4" in silver, black or brass.
Italian Leather 3-Ring Binder - Black – JB Custom Journals
MAGNETIC D-RING BINDER: The D-shaped, 3-ring binder frame has been designed with two extra-strong magnets. These magnetic binder tools will hold your
BinderRings Magnetic D-Ring Binder Mechanism (10 Pack), 3-Ring Binder 1-inch D-Shaped Rings for Standard Letter Paper (8.5 Inches x 11 Inches)
Signature 3-Ring Binder, 1.5 Rings, Reinforced Metal Corners, Laminated Patent Cover
Buy Letter Size 3-Ring Plastic Binder Mechanisms Online
Ring Binder Mechanism Overview & Options
Ring binder mechanism 2 D-ring, Magnetic (for glass)
Best Home Office Binder to Help You Organize Paperwork - Avery
Avery® Filler paper for 3-Ring/7-Ring Mini Binders
Shuokecrafts 2Pcs Metal Standard Letter Size 3 Ring Binder Mechanism,3 D-Rings, Replacement Kit,Loose Leaf Binding Spines Combs for Organizers Planners (25mm Inner Height) : Office Products