From Clairol
COLOUR + STRENGTH* + ZERO AMMONIA, ALL IN ONE. Clairol Colour Strong gives you multidimensional colour and reinforces the internal structure of your hair.* What's the secret? The continuous system with colour + bonding has AHA (alpha-hydroxy-acid) in every step: Bonding Primer, Permanent Colour and Bonding Treatment. Zero ammonia + 100% grey coverage. Sublimely multidimensional colour and hair strength*Colour Strong full kit vs. Colour Strong colour step only