X-Acto - Heavy Duty Blades - 5 Pack - X-Acto Heavy Duty Snap off Utility Blades fit X-ACTO X3243 and X3246 Heavy Duty Snap Blade Knives. Finest quality carbon steel for heavy duty cutting on wire, landscape fabric, dried caulk, wallpaper, carpeting, vinyl cord, rope, Mylar, canvas, poster board, foam board & mat board. X-ACTO does not offer this item in larger packages. This is the replacement for X-ACTO X443, which has been discontinued by X-ACTO. Includes 5 Blades.