They make a nice little light duty pen knife for a key chain or pocket. My dad was a fan of them, even though you couldn't cut him loose from his Case peanut with a blow torch. But when he was elderly, he had trouble with arthritis and in his later years carried a Christy knife.
The Christy Knife Company goes back to the late 1890's, and they made a patented serrated edge bread knife. In the 1930's, the head of the company, I forget if it was James or Earl Christy Sr. had a friend who suffered with arthritis, and this friend asked Mr. Christy if it was possible to make a small pen knife that could be opened without having to have a strong thumb and thumb nail. In those days there was no one hand opening knives like today's Spyderco's and other tactical's. Mr. Christy was a machinist, and came up with a model of the present day Christy knife. By the late 1930's the knife had become popular, and during WW2 it was sold in army PX's and Navy exchanges. The Christy company has in it's files, letters from service personel praising this little knife for service in some dire surroundings. One letter was from a Navy Pilot, who being wounded and without the use of one arm, used the Christy knife he had in the sleeve pocket of his flying coveralls to cut himself loose so he could bail out from his crippled Hellcat.
Unfortunatly for the Christy company, history passed them by, and by the 1970's things were tight, and the market change had them lingering on in a slow decline for many years. The small company couldn't compete with the new companies like Spyderco and they went out of business a few years ago.
Before they went out, some government agencies actually issued them out. The U.S. Custom's gave one to every graduating customs agent, as they were great for cutting open suitcase linings and other materials. The blade locking in a partly open position let it be used as a box cutter.
I know my own father had bought a lot of them. Years after he passed away, my mother had passed on, and my sister and myself were clearing out the old house in Wheaton, and Anne came on a letter from Mr. Christy to my dad, thanking him for buying 50 of the Christy knives for issue out to the personel in his section. This had taken place in the mid 1950's, and at that time there simply was no other knife like the Christy on the market. It was in it's day, a very unique little piece of hardware. Nowadays, just about every country gas station has cheap one hand lockblades for a few dollars. Time and things change.
Sometimes, I'm not really sure why, I slip dad's old Christy in my watch pocket. It still opens mail and UPS boxes just fine.
Carl.