AAA, single mode, but I got one of these. Nice, very tiny:
I’d probably go for a cree 7W 300, those could blind someone if needed. The last one I got, I think after last Christmas, was good. $2.50, single mode though.
If you ordered a few, might get good one.
I looked at the review of the Klarus, that might be a good one. $39.95 is pricey, but you can spend that, or more, on dinner.