Heathkit DX-20 CW transmitter
Like most Heath products, this transmitter was sold in kit form. Crystal controlled, (an external VFO was also available) uses 6CL6 as oscillator and 6DQ6 sweep tube as final. Rated at 50 watts input. An ad can be found in QST magazine, December 1956.
Try this link for Heath catalog info on the DX-20.