Manufactured by the French company Radiotechnique for the military. The tube features grey staples plates and a round dual supported halo getter. Grid support is made of copper. These produce a very detailed and transparent sound field without being overly aggressive. Date code is Sept, 1964. They have thick mica wafers which give the tube extra rigidity which minimizes any microphonic problems. The cathodes have been specially designed to withstand many on/off cycles and long periods in cut-off without any degradation of performance.