One multi tool to measure twist angle and WPI for spinners and knitters.
It has WPI guide, yarn twist guide and spinner's control card.
WPI tool and guide: just wrap you yarn around the tool and count how many wraps you have or simply lay the yarn along the grooves and find a match.
Yarn Twist tool: measure your twist angle to spin a yarn with a consistent twist.
14 WPI - Fingering
12 WPI - Sport
11 WPI - DK
9 WPI - Worsted
8 WPI - Aran
7 WPI - Bulky
5-6 WPI - Super Bulky