Cover FX Custom Cover Drops P20Cover FX\'s Custom Cover Drops allow you to add pigment to any product in your beauty regime. Add between one and four drops - depending on the depth of coverage you want- and transform your moisturiser, serum, oil, primer, foundation or tinted moisturiser, in an instant. These revolutionary drops feature Flash Fusion Technology™, so as soon as you drop, the solution flashes off leaving behind pure pigment, weightlessly transforming your favourite product, in the palm of your hand.