38% Phosphoric Acid, Blue Contains 38% phosphoric acid. Indicated for temporary canal treatment. Formulated for complicated cases requiring calcium hydroxide treatment. The formulation of Etch-Rite 38% Phosphoric Acid Etching gel optimizes its working and handling properties. It can be agitated to lower viscosity to offer a 15-second etch.Conveniently delivered through small-gauge, pre-bent applicator tips, the gel stays precisely in place and will not run onto exposed tissue. It washes off easily, leaving no residue.Etch-Rite Bulk Pack contains 24 (1.2 ml) syringes.