Delay 4301 L system building block
Digital Equipment Corporation (DEC)
||Etched in solder on the circuit side at the insertion end
||Stamped into the front of the aluminum frame (this number is also handwritten in black in on the side of the frame)
overall: 1/2 in x 4 1/2 in x 7 in
At one end of the bard there is a blue plastic connector. Bordering the rest is an aluminum frame. "DELAY 4301 L" is printed on the solder side above a grid lettered A-Z.