The clamp is typical of many bar clamps, with these components:

• A bar with semi-circular notches underneath, and a pin to keep the movable block from falling off the end;
• A movable block held by an iron stirrup that engages the notches;
• A fixed block with two holes;
• A single spindle with ferrule and central pin.

The mark includes the maker's name, and pictures of the products: two chairs (one mobile, one not), and a sanitary base desk.

It is apparently branded (thermographed) into the bar without the use of ink or paint.