This twist-up, crayon-like Bb. color stick is the perfect root touch-up product. I have light-brown hair, BUT color my strands black. I hate when my roots show, and admittedly, I have three grays (that I can see)! I dye my hair every three weeks, so my roots are maintained. I do however have very fine hair, and this color stick is great for filling in sparse areas. Just glide the twist-up pencil along your hair for perfect coverage. The formula is water resistant - don't worry about color running down your face, neck and clothes if you get caught in the rain. The stick is compact and takes a little while to cover your roots (or grays), but is great for travel and on-the-go touch ups.
The Bumble and Bumble Bb. Color Stick is available in five natural shades - blonde, dark blonde, brown, red and black. There are four limited edition statement hues - Ballet (pale pink), Lilac (purple-ish-blue), Flamingo (fuchsia), and Pacific (a vibrant blue). I'm not one for colorful streaks in my hair and it would be a challenge on black stands, but I can see how they'd enhance blonde hair.
This highly-pigmented color stick is a great temporary solution to roots and grays. Bumble and Bumble is my absolute favorite hair care brand - it's pricey, but worth it. You can purchase the Bb. Color Stick at Sephora.