The FailSafe PCR System is unique in that the optimal conditions for amplification are determined automatically by performing a single round of PCR, which is especially useful for solving tough PCR problems. The FailSafe™ PCR PreMix Selection Kit accomplishes this by using 12 different PCR PreMixes, which include buffer, deoxyribonucleotides, salt, and varying concentrations of magnesium salt and of the FailSafe™ PCR Enhancer (with betaine). The first time you use a specific template/primer combination, prepare PCR reactions using your template and primers with each of the 12 FailSafe™ PCR PreMixes. Analyze the PCR product from each PreMix reaction by agarose gel electrophoresis and visually determine which PreMix gives the best amplification: a single, strong PCR product of the desired length. Then use the selected PreMix for all subsequent amplifications with that template/primer combination. The product is called "FailSafe" because at least one of the 12 FailSafe PreMixes should give the desired product. Optimization is automatic. The time required for optimization of most PCRs is less than six hours, including DNA Purification, optimization and gel electrophoresis to confirm the best PCR PreMix to use in a reaction.