The 19HR6 is a type of vacuum tube (or thermionic valve) in which electrons pass from a cathode, through a vacuum and grid, and then to an anode. It is an Nuvistor tube, an early type of minature tube developed by RCA in the 1950s, which uses a combination of several elements to give it better performance than other types of tubes. The 19HR6 features a three-element design consisting of a cathode, grid and anode. It is a very low-noise device and is used in some guitar amplifiers, as well as for preamplifier, pulse amplifier, timer, and switching applications. The 19HR6 is a medium power, medium voltage, medium gain tube.