The GU-43B tetrode is used for wideband power amplification at frequencies up to 100 MHz in RF equipment. Early version of GU-43b tube by Svetlana factory. Silver-coated cooler. The GU-43B has similar characteristics to the 4CX1000 tube.

Cathode: indirectly heated, oxide-coated.

Envelope: glass-to-metal.

Cooling: forced air.

Height: at most 125 mm.

Diameter: at most 100 mm.

Mass: at most 1.0 kg.