This is the perfect tiny needle gauge tool for travel-knitting. The big squares or rectangles are okay for at-home knitting, but clumsy for travel. The Cocoknits needle gauge is a joyous rainbow stack of connected discs for identifying knitting needle sizes US 0-15 / 2-10 mm.   
 
And because Cocoknits is committed to avoiding plastic wherever possible, their needle gauge is manufactured from PLA, a 100% biodegradable, plant-based plastic substitute!
 
The discs swivel out and click back together with tiny magnets (which makes it as much fun to play with as use) and the whole rainbow tool is small enough to pop into the Accessory Roll so you'll never leave home without it.
 
Use: Swivel out the disc to access the hole and insert your needle. The smallest hole that your needle fits into is your needle size. If the needle is unable to be inserted, select the next size up, or if there is excess space, try the next size down.