Gauge: 21sts in 4inches (10cm) in stockinette stitch, row gauge is not important in this case.

You will need:
DK yarn (up to 100 grams for the smallest size, up to 200 grams for the largest size), knitting needles to obtain the gauge (for knitting flat) and one size larger knitting needles (for knitting in the round), darning needle.
The hat part of the balaclava is knit flat.
The neck part is knit in the round (on one size larger knitting needles).