http://www.ebay.com/itm/G-M-CO-ADJUSTABLE-WRENCH-HAMMER-NAIL-TACK-PULLER-L-I-CITY-NY-USA-UNBREKABLE/201062119297?_trksid=p2045573.c100034.m2102&_trkparms=aid%3D555012%26algo%3DPW.MBE%26ao%3D1%26asc%3D20643%26meid%3D5851444365894076148%26pid%3D100034%26prg%3D9209%26rk%3D5%26rkt%3D8%26sd%3D231192431787..................early multi tool and box opener

I have one of those, had it for about 20 years before I learned that the slot on
top was manufactured that way, I had thought that someone got carried away
with a hacksaw.

Is an odd feature. Perhaps for the other end of the spring?