I wonder why they don’t make these. They have size 11 and 13. Why not just call the size 13 a 12? Seems just like the crochet hooks. No “A” crochet hooks. Just goes right to "B."
Why is that?:??
The difference is only 1mm so I guess they figure if you’re knitting at that gauge that won’t make any difference.
I think that what Jan says must be the case–I’ve never seen size 14s or 16s either, but there are 15s and 17s…
I’m also pretty sure that there are some sizes (in milimeters) that are available in the US but not in Europe and vice versa…:shrug:
It is pretty odd, isn’t it? We have 0-10, 10 1/2, 11, [B]NO 12[/B], 13, [B]NO 14[/B], 15, [B]NO 16[/B], 17, then we skip all the rest and go to 35, skip some more and go to 50.
How’s that for math?! :yay: 
Well I heard about this investment guy down south…
If you look at them in mm it’s even odder; a 10 is 6, then 6.5, 8, 9, 10, 12. No 7 or 7.5mm, though they have them in Europe, and no 11mm, skips from 15/10mm to 17/12mm. Then a 19 is about 20mm…
here’s a link to a conversion chart for US/UK/Metric. Hope this helps. (also for crochet)
8.5mm needles (which I assume would be a #12US) are available here in Holland. I have no idea about the U.S.
No we don’t have that size here in the US. That’s why I’ve heard knitters talk about a 12 needle, I always figured they meant 12mm.