How many shots can you get from one can?

Don't know yet, hope I never find out. But I have "fired" 4-5 short bursts so far and there seems to be plenty left in the can. Each time the barking stopped and the dog left. My rule is that a barking dog behind me is in an attack position; if it closes it gets a shot. A dog that actually attacked would get a facefull, not a warning shot.

What is the active ingredient in this product? Thanks.

Capsaicin and Capsaicinoids 0.35%. Other ingreds contain Petroleum Distiiate 99.65%. This stuff works very well and is effective. I do recommend this product and carry it whenever we walk our dog.

Does this product have an expiration date? If so, how far out is it?

I sent www.halt.com an email 11/10/14 and as of this comment, no response back - yet. Nothing noted on containers for shelf life or expiration date.

How is this any different than standard pepper spray? Just branding ?

It's not, other than the potential for strength differences between products. Mace is a brand that uses capsaicin pepper spray as well as tear gas. I'm not sure if tear gas can cause any complications for dogs or not.