Ok, I give up. What in the world is this thing? The knurled knob end is stamped “No. 148” and “Atmars Tool Co. Dakland 12 California”. The “business” end is shaped like a very short screwdriver blade, with a center section that rotates when you push on the knurled end. My grandfather left me a bunch of tools, some automotive, some small engine, and others from a foundry. Anyway I’d love to know what this is.