Mullard Magic: For All Your Vintage Valve and Radio Needs!
CV1377, Military Spec, Brown Base, GZ34, Mullard, f32 B5K4, Blackburn December 1965 manufacture
CV1377, Military Spec, GZ34, Mullard, f32 B4F1, Blackburn June 1964 manufacture
GZ34, Mullard, f31 B9H, Blackburn 1959 manufacture