The thermal cycler (also known as a thermocycler, PCR machine or DNA amplifier) is a laboratory apparatus most commonly used to amplify segments of DNA via the polymerase chain reaction (PCR).[1] Thermal cyclers may also be used in laboratories to facilitate other temperature-sensitive reactions, including but not limited to restriction enzyme digestion or rapid diagnostics.[2] The device has a thermal block with holes where tubes holding the reaction mixtures can be inserted. The cycler then raises and lowers the temperature of the block in discrete, pre-programmed steps.