Needle/Hook Gauges

Knitting needle gauges are flat knitting notions with holes in varying sizes. The holes correspond with the size of different needles, so you can use the holes to measure the size of a knitting needle. Crochet hooks can slide into the open holes.

Needle gauges are often paired with a knitting gauge ruler, which are short rulers that are great for measuring your swatch...  (yes, you need to swatch!!)