This pattern is written in US terms. It is worked in two pieces, beginning at one shoulder across to end of opposite sleeve. The second sleeve is worked by joining at base of the foundation row and worked in the opposite direction. This helps insure uniformity with the sleeves. Sizes are given for small, medium and large with changes in parenthesis S(M, L). A second download is also available which includes sizes XL (1X), 2X, and 3X.

Stitches:

hdc = half double crochet
blhdc = back loop half double crochet
blhdc dec = back loop half double crochet decrease
blsc = back loop single crochet
blsc dec = back loop single crochet decrease
sl st = slip stitch
Materials:

Worsted weight yarn (Weight 4). The shrug shown is made using I Love This Yarn Colors, Madrigal. I also used Loops & Threads, Impeccable in various colors.
Size N (9 mm) crochet hook
Tapestry Needle for weaving ends
Gauge:

4 rows x 8 stitches = 3? x 3?