These hand warmers are perfect to brighten up cold and dark winter days! It works up quick, and is knitted flat, so a nice project for the beginner knitter. The patterned section is easy to memorize, and only uses purl and knit stitches.
The yarn I used is a single ply sock yarn, and fairly thicker than the average sock yarn. This means that if you use multi ply sock yarn, you need to check the gauge.
The finished measurements are :

wrist: 14 cm wide
top of hand warmer: 20 cm wide
height of hand warmer: 12 cm

Because of the ribbing at the wrist and the top it has a lot of give to it, but if you are unsure, you can always add stitches as you go, and look if it fits your hand well.

The dutch version can be found as a link on the pattern webpage.