And please, please be careful when you use it. I don't remember the exact expansion ratio when liquid nitrogen becomes a gas, but it can readily displace oxygen in a confined area. An oxygen monitor is not a bad idea. It only takes a couple breaths in an oxygen deficient enviroment before you will pass out and die. Really.
A face shield, apron (not cloth--something that will shed liquid), and cryo gloves are also good. Eye protection under the faceshield is a good idea. Cover your skin--don't be barefoot or wear shorts.
And if you can't resist the urge to dunk something in LN2 and then whack it with a hammer to see it shatter, use eye protection. And remember when the stuff melts it can make a royal mess and you will have a devil of a time finding all the remnants. (Chewing gum dipped in LN2 & shattered is a b1tch to clean up. Trust me on this one.)