Go to the website of O'Reilly Auto Parts — oreillyauto.com — and search for the part number "121g."
NOW!
If you are like "No I am too lazy to search it just tell me now" well if you searched it you will see a product listing for a "flux capacitor."
Yes, A FLUX CAPACITOR!
If you are still asking what is a Flux Capacitor it is a core component of the time-traveling car in the classic 1985 flick "Back to the Future."
"Flux Capacitor requires the stainless steel body of the 81-83 DeLorean DMC-12, V6 2.9L to properly function," the product description reads. "Once the time machine travels at 88 mph (142 km/h), light coming from the flux capacitor pulses faster until it becomes a steady stream of light. Then, time travel begins."
"Time Travel at your own RISK!!!" the company warns, noting: "Plutonium not Available at O'Reilly Auto Parts."
"1.21 Gigawatts," it adds, channeling its best Dr. Emmett Brown impression.
Unfortunately you can't actually buy a flux capacitor from the Springfield-based auto parts giant. The page states that the product is a "Non-Functional Item Displayed For Entertainment Purposes Only."