The Series 5500 reactors are based on the popular 4560 and 4590 line of Mini and Micro Reactors. A redesigned compact magnetic drive, stirrer motor, and aluminum block heater that also serves as the stand keep the size and costs down. These systems will interest not only the the user with limited space or budget, but also the user looking to build a cost-effective multiple reactor system for combinatorial chemistry or high throughput investigations.