This month's item turned out to be a real brain-scratcher, mainly because we were unable to find another one just like it anywhere. Even the manufacturer, Mac Tools, wasn't able to help. They discontinued production of this screwdriver years ago, and even their most senior workers were unable to identify it. We're calling it a variation on a tamper-proof spanner screwdriver, used to remove tamper-proof screws.

Spanner screwdrivers are commonly used in the auto and aeronautic industries. Glen S., who identified the item, used one for 30 years in the elevator industry to remove elevator panels. We believe this one is circa pre-1960, when wood began its demise and plastic became the material of choice in tool production.

What makes this tool unique to all the others we found online is the raised surface between the two prongs. Without the prongs, it would be a dzus tool, denoted by the rounded tip. Its purpose is the same as that of the spanner screwdriver, to remove special tamper-proof screws.

To better understand how these tools work, check out some of these tamper-proof screws. Needless to say, there are as many variations of spanner screwdrivers as there are specialty screws. To enlarge the pic above, click here. To view a close-up of the head, click here.

Congratulations again to Glen S., of Nashville, TN, who identified this month's item!