Unknown.UNUSUAL CLOCK KEY WITH WRENCH IN BOW. Unknown. Steel. No. 10 (4.75mm). 2 1/2 l. A hexagonal opening is the only perforation in the bow, which, lacking any aesthetic purpose, I assume to be wrench. Average use withpartial tarnish. NOTE: Shipping for this item via 1st Class Mail is $3.00. Your shipping charge will appear as $4.00 in the Shopping Cart, but will be lowered before your credit card is charged.