The comprehensive 3X Series portfolio comprises of a single range of low toxicity, blend-able Ampreg™ 3X hardeners that can be used in conjunction with the following resins:Ampreg™ 30 Low viscosity Resin: replaces Ampreg™ 21Ampreg™ 31 Drainage resistance Resin: replaces Ampreg™ 22Ampreg™ 36 Premium ..