No. 2.1 deep blue is a dark blue shade, which is only effective for clients with light blonde to blonde hair (on darker hair we recommend to use RefectoCil No.2 blue black). RefectoCil No. 2.1 deep blue is a color for fashionable clients, who wish a perfect match of their hair to blue eyes or blue eye make up.
MSDS Spec Sheet
RefectoCil Quick Reference Guide