iBond Etch 35 Gel and iBond Etch 35 Fluid use the traditional strength of 35% phosphoric acid. iBond Etch 20 Gel, with 20% phosphoric acid, provides just enough conditioning of enamel and dentin, resulting in less loss of tooth structure and equal bond strength compared to more aggressive concentrations of etchant. Both gel products are blue, are applied precisely and easily with cannulae or brush tips, and are easy to recognize in use.