Ballpoint pen knife

They first appeared as custom-made pens from various custom knife makers, and were later mass-produced by other companies.

Pen knives such as these are designed for self-defense due to their ease of concealment.

There are many versions, including variants with special purpose razors for shaving.

They have an array of foldaway blades and tools including knife, scissors, file, opener, screwdriver and battery-powered light.

Ballpoint pen knives, because they allow a knife to be disguised as an innocuous object, are subject to restrictions or prohibitions in some jurisdictions.