The DTF104B is a Numitron display tube produced by RCA. Internally, it is nearly identical to the more common DR2000, but it is designed to be read from the top rather than the side. A spot exists on the backplate where a left decimal point could have been included, but it lacks filaments and is therefore non-functional on this model. Its flat top gives the DTF104B a distinct look and helps reducing reflections from adjacent tubes.