So anyways the model number engraved in the stapler is T-25M, but the single-sheet exploded parts view inside the packaging says it's a T25P Gun Tacker.
The printing on the blister-pack packaging says I'm supposed to use T-25 staples.
It lists a bunch of other sizes that (I guess) are possible if you have the right stapler:
T18 (3/16" - 5 mm) T25 (1/4" - 6 mm) T37 (5/16" - 8 mm) T75 (1/2" - 12 mm)
I had been to another hardware store a week ago and picked up some T20 staples (for my other gun, which is the same model as this gun) and they work fine in this T25 gun (and these T20 staples are made by Arrow), but it's got me scratching my head wondering why the T20 size doesn't show up in the above list.
The Txx naming system seems to be trade-marked by Arrow, but I'm wondering what the hell it's supposed to mean, and what exactly is the difference between T20 and T25.
It always pisses me off that they don't indicate the actual width (in inches, mm, etc) with these staples. It's always according to this strange Txx code.
And why is it that only Arrow seems to make staples for these guns?