ChiaoGoo Double-Sided US-Metric Swatch/Needle Gauge Chart
You can use the chart from ChiaoGoo to convert knitting needle sizes or crochet hook sizes.
Front Side – Knitting Needle Conversion Chart. Types of yarn and recommended needle size.
Back Side – Crochet Hook Conversion Chart. Types of yarn and recommended hook size.
Size 5.5” x 5.5”