W501 module with green substrate and a tan, plastic extraction handle attached by two rivets. Handle reads "DIGITAL EQUIPMENT CORPORATION MAYNARD, MASSACHUSETTS." Reverse side of substrate(with solder joints) reads " SCHMITT TRIGGER W 501F 11-66" along the edge. Obverse side has several components and is marked with three inspection stamps; one is barely visible. "FLIP CHIP" can be read through substrate, between rivets. Repeating "NELCO" pattern in red print barely visible on substrate.