Samsill 16303 Antimicrobial Locking D-Ring Binder For 11 X 8-1/2 Sheets, 5 Cap, Red Antimicrobial locking Angle-D ring binder with back-mounted rings, label holder and two inside pockets. AgION antimicrobial additive prevents the growth of bacteria, mold and fungus. Papers stay neatly in place with locking Angle-D rings. Angle-D rings hold up to 25% more sheets than standard round rings. Rings mounted on back lid so pages lie flat and reduce wear.