Utility knife blades, snap-off, quick-point. 8 cutting points blade, size is 4-1/2 inches, card of 3. Number 11-301 fits numbers 10-218, 10-480, 10-380, 10-280, 10-220, 10-418, 10-151 and most other 4-1/2 inches, 18mm snap-off blade knives.