Philco Prototype Rectangular CRT
This tube uses a 10BP4 gun, requiring an ion trap. The base of the neck looks like the 12DP7 WW2 radar tube. The face is about 14 inches diagonally. The glass is distorted and appears to have been hand worked. The tube came from a Philco engineer, and may have been a prototype of a rectangular tube made by Philco, or it may have been the individual work of the engineer.
The tube was generously donated to the Early Television Foundation by Darryl Hock.