iBond Etch Gel & Fluid Fluid, 15 ml. 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 compared to more aggressive concentrations of etchant. iBOND Etch 35 Gel uses the traditional strength of 35% phosphoric acid. Gel product is blue, and is applied precisely and easily with cannula or brush tip and is easy to recognize in use.