Foolproof Haircolour Air-Activated: Innovative formula uses oxygen in the air to preserve hairs subtle variations. Shuts Off: Shuts off so it can't over colour. Always looks natural. Easy: No mixing, no mess. Just comb in, shampoo out. Takes only 10 minutes. Gentle: No peroxide and no ammonia formula makes it the gentle haircolour. Traditional haircolour products contain peroxide and/or ammonia, and can over-colour hair making it look unnaturally dark and flat. This Just For Men innovation is activated by oxygen in the air instead. It preserves the natural, subtle variations in your hair.