Before delivery, warm the product to room temperature before opening, otherwise the brush may break. Acid Free Primer / Adhesive Agent, Acid-Free The Acid Free Primer is an acid-free adhesive agent that does not fully dry and leaves a sticky layer on the nail. It should be applied thinly, as it acts like double-sided tape between the nail plate and the material applied on top of it. If too much of the Acid Free Primer is applied, the material applied afterward will not adhere properly to the nail plate and lifting may occur. Excess material should therefore be wiped off at the neck of the bottle or dabbed on a paper towel to ensure that only the necessary amount of primer is applied.