I received some snap picks from Raimundo a while back, and here are some long overdue pictures.
The principle is very similar to how bump keys work; you snap the bottom pins and the momentum transfers to the top pins and springs. While applying torsion to the plug, the pins can clear the sheer line and allow the plug to turn, opening the lock. (I won’t bother with the billiards analogy)
These snappers are handmade from bicycle spokes. They feature a curved handle to make them easier to hold, a thumb guard to make snapping easier and reduce the stress on your thumb, and one of them has an “eggtooth” on the blade. The eggtooth is a divot towards the front of the blade that makes it easier to find the last pin. This is helpful because striking the cylinder or tailpiece would take a lot of energy away from the pins.
It takes a little bit of practice, but it makes a very quick way to open many locks in a hurry.