This has four guides to assist making the sizing circle (finger rail) for rings. The guides are based on the US (North American), UK, Indian, and Asian/South American ring sizing systems. NOTE: these are just numbers I got off the internet (mainly wikipedia's ring sizing article) and these guides may contain errors. The only one I used personally was the US/North American system. Please use with caution in production settings as some of the sizes may be incorrect (and if it is convenient, please point out any errors you find...thank you).