Binary To Octal DEC 1151D System Building Blocks
Digital Equipment Corporation (DEC)
||Etched in metal on top part of frame.
||Etched in the metal on right side of frame.
overall: 7 in x 4 1/2 in x 1/2 in
Printed circuit board in an aluminum frame with many components that include: resistors; transistors and capacitors. "4153" etched on frame.