Here are some key features of a snap-off blade knife:

• Retractable blade: The most distinctive feature is a retractable blade that can be extended or retracted using a sliding mechanism or button. This protects the blade when not in use and reduces the risk of accidental injury.
• Snap-off blades: The blades are typically made of segmented, high-carbon steel and are designed to be snapped off when the cutting edge becomes dull or damaged. This maximizes blade usage and reduces replacement costs. There are different blade thicknesses available, depending on the intended use.
• Ergonomic handle: The handle is designed for comfortable gripping and can be made of plastic, metal, or rubber.

Here are some common uses for snap-off blade knives:

• Cutting cardboard boxes: This is perhaps the most common use for snap-off blades. The sharp blades easily cut through cardboard without damaging the contents inside the box.
• Cutting carpet and linoleum: Snap-off blades can be used to cut carpet, linoleum, and other flooring materials.
• Opening packages: The knife can be used to safely open packages, envelopes, and other sealed items.
• Stripping wires: Some blades have features for stripping insulation from electrical wires.
• Light-duty trimming: They can be used for light-duty trimming applications, such as trimming branches or foliage.

Here are some additional things to consider when choosing a snap-off blade knife:

• Blade size: Standard blade widths are typically 9mm or 18mm. A wider blade is good for heavy-duty cutting, while a narrower blade offers more precision for detailed cutting.
• Blade locking mechanism: Some knives have a mechanism that locks the blade in place to prevent accidental retraction.
• Number of blades: Some knives come with a dispenser in the handle that stores extra blades.

Overall, a snap-off blade knife is a handy and versatile tool for various cutting tasks around the house, office, or workshop. They are relatively inexpensive, easy to use, and safe when used properly. Just remember to replace dull blades and dispose of them safely.