The CAP ALUM POLY 390UF 20 is a type of capacitor that features 390 microfarads and operates at 6.3 volts with an aluminum-polymer construction. It has a radial, can design suitable for surface mount devices (SMD) and a resistance of 14 milliohms. The product boasts a lifespan of 2000 hours when exposed to temperatures up to 105 degrees Celsius.