Are you referring to the round, 3 oz. flask with the Jameson imprint?...the round ones that come from Britain...
I bought one a while back on eBay. I've found the size to be just right for my needs. However, the round shape makes it slightly awkward to hold, the screw cap can be dropped, and the cap takes at least nine, full-bore twists to remove. If your wrist isn't supple, it may take twice that many.
I miss the convenience and security of my larger, rectangular flask with a captive cap and one-third the amount of screw thread.
I continue to look for the perfect, small flask for my needs. Prompted by your post, I may have found it here .