The actual opening size is 5/8″, I think the 7/16 is a British Standard / Whitworth size. It is in fine shape, there is a number (2) stamped on the back.
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Antique 4-Way Barcalo Wrench 1/2” X 7/16″ Open-ended Square Nut Farm Hand Tool
Used wrench BARCALO 7/16” X 1/2” Made in America 🇺🇸 Fast free shipping
4 Way Alloy Triangle Square Universal Key 15/64 5/16 3/8 Inch Stainless Steel
Reach different fasteners — includes 15/64, 5/16 female square, 3/8 triangle, and skeleton key. Open a valve or cabinet lock fast with this 4-in-1 utility key. It combines four common shapes in one compact stainless steel tool.