Thermal cyclers (PCR machines) are commonly used for performing Polymerase Chain Reaction (PCR) reactions. This method was invented by Kary Mullis in 1984, providing researchers, scientists, and physicians with the ability to rapidly and easily amplify billions of copies of a nucleic acid sequence with much greater speed and convenience than traditional manual methods. Thermal cycles come in simple and gradient types. In the simple mode, the machine can simultaneously set a specific temperature for the samples, while in the gradient mode, multiple temperatures can be applied simultaneously. Denagene Tajhiz designs and manufactures both the standard PCR model and the gradient PCR model.