The CAD SN210 is a dynamic microphone that is designed for use on snare drum. I've only used it in the recording studio, but you could definitely use it for live sound reinforcement as well. I don't believe that the mic can be purchased on it's own, as I think it's only available in one of CAD's drum packs. The reason I'm not sure is because I've used it in a studio that I didn't own, so I wasn't really sure of it's origin. The mic has a super-cardioid pick up patter and will pick up frequencies between 90 Hz and 14 kHz, which is definitely okay for using it on a snare drum as you don't need that low end or super high end in there anyway as it would most likely be noise or unwanted frequencies. The mic also has a built on clip that makes it extremely easy to place on the snare drum.
While the CAD SN210 does have an adequate sound, it isn't one that I was blown away by at all. I do think that it can get the job done, but since you can only buy it in a drum pack, I don't think it is one that I can recommend. Unless you are really strapped for cash and are just looking for a set of drum mics to get you started with, I don't think that pre assembled drum packs are the way to go in terms of putting together a good set of drum mics. The SN210 is built well enough and definitely has the convenience of being able to place it quickly and easily, but for me it just wouldn't be worth having to get the entire drum pack. I should mention that I don't know the make up of the drum packs that include the SN210, however. The bottom line when it comes to recording snare drum for me is that I really don't see a reason to record it with anything other than a Shure SM57, which is definitely the industry standard for a reason. Having said this, if you do come across the SN210 and need to record snare with it, I don't think that you'll get a particularly bad sound, but there just are other ways that I would go when it comes to recording snare drum.