MP/Pen, MAZDA, GLOBE ENVELOPE, B7, 7 PIN BASE, AC/PEN, 7A2, A70B, APP4A, CV1174, KT42, MKT4/7, N40, Pen4VA,

MP/Pen, MAZDA, GLOBE ENVELOPE, B7, 7 PIN BASE, AC/PEN, 7A2, A70B, APP4A, CV1174, KT42,  MKT4/7, N40, Pen4VA,

The B7 based Mazda AC/Pen was introduced in 1933 and is an indirectly-heated power pentode at a level of 3 - 5W.

The envelope contains a bright cylindrical anode with clearly visible grids. The electrodes are held in, or clamped to, a glass pinch, from which wires will run to the spring base pins.