Mesa Boogie 5U4GB Rectifier Tube
The MESA Boogie 5U4GB rectifier tube is their tube of choice in the production of all new Mesa amps featuring this tube - Based upon classic 1950's technology, the 5U4GB is a vastly improved 5U4 design that is extremely reliable and consistent, as well as much more compact.
Mesa tubes are hand selected and tested for quality. This Mesa 5U4GB rectifier tube is recommended by them for their dual rectifier amps but are also a good choice for any amp using tube rectifiers. What you'll get is a traditional "vintage sag" with an elastic and compressed feel
It is basically the size of a 6L6 power tube, so please take special care to install them in the correct tube position, especially when replacing 6L6's at the same time