Most packs include basic rainbow colors — red, orange, yellow, green, blue and purple/indigo/violet — and many refill mixes add extra shades such as pink, red-violet, teal, electric green and midnight blue.
Most listings indicate these tablets are intended for children aged 3 years and up.
Ingredient lists commonly include fizz- and baking-related ingredients (for example, sodium bicarbonate, citric acid, sodium sulfate, sodium carbonate, PEG-8) and colorants (e.g., Blue 1, Yellow 5, Red 33/44). Some formulations are described as moisturizing and list agents such as vitamin E and shea butter.
Open the brush, insert a tablet, and close it. Dip the loaded brush into bath water and paint streaks or swirl to mix and layer colors on the water or tub surface.
Product details commonly recommend the tablets for normal skin. Several mixes are described as moisturizing and enriched with ingredients such as vitamin E and shea butter.