What kind of device is a dive knife classified as?

A dive knife is primarily classified as safety equipment. This classification reflects its crucial role in enhancing diver safety during underwater activities. The knife can serve multiple safety purposes, such as cutting away entanglements caused by fishing lines, nets, or other hazards that a diver might encounter. Its accessibility in emergency situations can be vital for preventing injuries or enabling an escape from perilous circumstances.

While some may see it as a diving tool due to its functional applications in underwater environments—like cutting through materials—its primary designation as safety equipment highlights its key role in ensuring a diver's safety and ability to respond effectively to unexpected situations. Other options suggest different applications, but safety is the foremost concern in underwater contexts, making this classification particularly relevant.