Phusion Hot Start Flex 2X Master Mix offers robust high fidelity performance and room temperature reaction setup in a convenient master mix format. The addition of an aptamer-based inhibitor allows room temperature reaction setup. The convenient master mix formulation is supplied at a 2X concentration and contains dNTPs and Mg++, requiring only the addition of primers and DNA template for robust amplification. Reactions can also be optimized using the provided DMSO solution.