There are a bunch of laws about brass knuckles, switchblades, and other things, but in the US, most states have yet to pass legislation on ownership of expanding batons, but rules on carrying them do vary. I know a few states actually require police certification if civilians want to carry them. The best way to find out the different laws is to talk to your DA. Until recently I thought that they were illegal in michigan because of a couple different idiot cops and a uniform store. (Again, talk to your DA.) I have and love both a 26" and 31" ASP. Although I highly reccomend JL USA for buying baton(s) I definitely wouldn't buy that piece of crap you posted the link to. Armament Systems and Procedures is the finest company in the buisness in my opinion, and you simply don't need a cheap imported spring loaded baton. A regular one will extend as quickly as you could possibly need, plus you can get replacement parts which you are less likely to need anyway.