We camp every summer and have used cardboard to protect our sharp knives and our fingers, but have had multiple close calls (from getting cut). So we purchased the 4-piece set of these blade guards and are impressed the safe, non-slip design. The blade does not rattle in an enclosed shell, but rather is held snuggly in the case by two tight pads on both sides of the blade (4 total pads, see photo). Another reviewer mentioned that the guard is hard to open, but that is because the blade is held tightly, which we like. If you are looking to protect your knives (and your fingers!), buy these guards. KB