SYLVANIA / JAN-CHS-6B4G 2 plates
The socket will be a US socket with a 2A3 6.3V tube. This is a popular 2-piece plate.
Made in America by Sylvania.
This is a valuable two-plate tube instead of a connecting plate.
It appears to be NOS, but since it is unknown, I will list it as a used item.
Comes in white box.