Ruling pen from a drafting took kit used by John S. Chase

Ruling pen from a drafting tool kit used by architect John S. Chase. The pen has a black handle. The plastic handle is connected to the metal top with a grooved join. The top of the ruling pen has two (2) metal prongs with a screw in the center to adjust the width of the opening. The screw is engraved with [RIDGWAY'S GERMANY]. The prongs are tapered at the end.