US Sizes are not universal; its good to know what milimeter your needle is.
Very handy, extremely affordable gauging and needle measuring tool from Knitter's Pride. Includes a plastic lense to magnify stitches for easier counting.
This needle gauge has always caught my eye. I like it because it has more needle size holes than any other gauge - 24 in total. Just compare. It lists the metric and US needles sizes as well as Crochet Hook sizes. It starts at 1.5mm through 19mm. This gauge is made in the USA and uses a special ink that prints crisply and will not wear off.
Contains US and (and the more accurate) mm sizes on one size, and imperial sizes, inches & cm ruler on reverse. Ever notice that there are 2 sizes missing between the US #10.5 and US#11 needle? Yup! the 7 and 7.5mm sizes!
Contains US and BWG sizes on one size, and corresponding (and more accurate) mm sizes on reverse. Another great needle gauge that includes the 7 and 7.5mm sizes!
very small US#000 (1.5mm) thru US#15 (10mm), including the more rare 7mm size.