.2mm nozzle

Depends on what you're using it for. I've got AB's with .15, .20, .30, .35 and .40 nozzles. When I apply base coats, I use the .30 and bigger. When I paint detail on train models or camo, I use the .15 and .20. For the detail work, I don't think there's anything better.

I use 0.2 in an H&S, i use it in preferance to 0.4 + 0.6 on all colour work, but use the larger needles for clear coats.

I have found the 0.2 give by far the better finish for me (Tamiya Acrylics).