I have a really old Snap-on that came from a swap meet, and bought the other three sizes off the tool truck. They were surprisingly affordable, unlike most tools off the Snap-on truck.
I also have the bigger size in a socket tip, also old Snap-on. I've used that one a good bit with an impact driver to remove really stubborn screws. The latest was on the door latch mechanisms on my '62 Suburban's rear barn doors, and the screws that held my dimmer switch to the floor. They were extremely corroded, and without hte impact driver I'd have had to drill them. And that's never fun.
That size is also used in the doors of my truck, for the window regulators if I remember correctly.
A very, very handy tool to have.
The smaller sizes have been used to rebuild Holley carbs.
Check out the Snap-on website. You should be able to get all you need from there.
-Brad
