Will work, but messy!
These worked OK. If you get them wet and go over the hair multiple times it will color the hair. However, it made a huge mess all over my hands and table. That could be partially user error as I was flying by the seat of my pants getting my daughter's hair rainbow colored for her Halloween costume. This is the only hair chalk product I have used so I can't honestly say how they compare to others. They work, but it's messy.
Rating: 3 stars