A PCR machine is required for every single procedure, test, or experiment involving DNA that you can think of. It is good for replicating DNA a few billion-fold, but is most often used to amplify specific sequences of DNA strands, which is extremely useful in diagnosing any disease or condition based in one's genes. Typically, PCR machines cost thousands of dollars and are used by high-end labs, but I want to see citizen scientists, students, and hospitals use PCRs as often as possible, for both medical diagnosis and advancement of the Life Sciences. I succeeded in designing a plausible, mass-producible version of a sub-$100 PCR by stripping high-performing and expensive designs' unnecessary complexities, making the sole concern of the device a matter of simple heating and cooling. Instead of aluminum heating blocks, my rack holder uses air convection and nichrome wire. Instead of sophisticated motherboards controlling the electronics, I used an extremely simple USB-enabled microcontroller (the PIC18f2550). I want third-world countries and college students to all have access to this technology, as it would enable all forms of experimentation and testing DNA, especially for genetic conditions, both simple (test if you're related to your father) and complex (see if someone has a genetic propensity for hormonal deficiency).