You can use left over yarn for this project. You need fingering yarn in five colours. Any fingering yarn will work, the ones I used are suggested in the details

Gauge

x-small 36 / 40
small 33 / 36
medium 30 / 32

Needles

Use needles that give you the right gauge. I worked with needles 2.5 mm (cuff) and 3 mm (mitten body and thumb) to get gauge for medium size mittens (US 1 ½ and US 2 ½ ).

Use you preferred type of needles for working in the round on small circumferences.

This pattern was a mystery knit in the I make mittens group in January 2014.

It is now available as a normal pattern.