This 384-hole heater is designed for integration into high-throughput polymerase chain reaction (PCR) thermal cycling applications. It is profiled to maintain optimum temperatures uniformly across a 384-well PCR sample block (approximately 16 x 24 in.) while rapidly cycling the reagents in the wells through the three required cycle steps. A proprietary trimming method for thin flexible heaters allows a tight hole-to-hole tolerance and provides almost perfect registration of the heater to the PCR sample block. This allows the reaction process to be viewed without infringement by the heater. It responds to the industry's growing movement away from use of the 96 hole micro plates.