It's called a Sheepfoot blade because it looks like the rounded end of a sheep's hoof. Emergency responders and EMTs, ranchers and river guides by and large carry rounded tip-free blades because they can't poke or puncture inflatable watercraft, livestock or people. Spyderco's classic Rescue Model is basic fundamental gear for emergency cutting and has been since the 1980s. 2007 sees the Rescue available for the first time with an Emerson Opener.

Ernest Emerson, knife designer and owner of Emerson Knives, popularized and patented the opening feature which is a horn, protruding from the top of the blade that catches a pocket's edge or belt when drawing the knife. It opens the blade quickly in one motion. The Spyderco Rescue Emerson Opener opens traditionally as well with the Trademark Spyderco Round Hole and its blade is fully SpyderEdged (serrated) for zipping through rope and woven materials. The blade is flat-saber-ground VG-10 stainless and full-thickness at the spine, from heel to tip, for rigidity and strength. Its' gray fiberglass-reinforced nylon handle expands wider at the front and back end with a cut out, positioning the index finger so there is no slipping when cutting and pulling.