Maco 300 chrome top,like mine is supposed to have 5 M2057 tubes in there,but the 8950 will work it just will not do as much. The m2057 tube was a beefed up 8950 tube that Maco had GE redesign(that is the rare Maco 300,1x4). and i was told,never did it, you can run all 8950 tubes as well...