utility knives snaps off in segments to remove worn cutting edges and expose sharp ones. Their sliding lever moves the blade strip into and out of the knife handle to retract and extend the cutting edge. A utility knife is generally six inches long and works well for slicing fruit, tender pieces of meat, or sandwiches. As the “knife of all trades,” it's a handy go-to for the everyday chef. “Snap-off blades have so many advantages: they allow for longer blade exposure; they're convenient, safer, versatile and always ready to use – and you'll have quick access to fresh, always-sharp blades. OLFA® STAINLESS STEEL™ blades are sharper than most other snap-off blades in the world, and rust-proof. This makes them perfectly suitable when things can get a little wet or moist. Utility knives are used to cut and trim a variety of building materials including: drywall, felt paper, wallpaper, rope & twine, plastic sheet material, fiberglass insulation and more. They can be divided into 3 general categories, Retractable Blade, Fixed Blade and Snap-off Blade. Utility knives usually only expose about 3/4-inch of the blade, so you have a limited cutting depth. Snap-offs retract around a couple of inches if you need to make a deeper cut in something like foam insulation.