WHAT'S LEGAL:

Your lockblade folding knife should have a thumbstud, thumb"hole", thumb "disk" or similar push-thingy, so long as the "thingy" is attached directly to the blade (versus on the grip and linked up via a gearbox of sorts). It should not have a spring that does ALL the opening (yes, the Kershaw Ken Onion series seems to be OK). And finally, the blade needs to have at least some tendency to stay closed in the pocket or whatever bias a "bias towards closure" or "detent" (discussed in more detail later in this chapter).

As long as it's got all that, and the vast majority (including all eight knives discussed at the bottom of this document) do, it cannot be "declared a gravity knife or switchblade" even if you can snap it open with relish :). And you can carry it concealed so long as it's concealed in the FULLY closed position, or open-carry if that's your thing (not recommended for BIG stuff, in case you happen on a town with a funky local ordinance or a really cranky cop).

There's no length limit. Seriously :).