Here is a locking gas cap That is in good shape.  I don't have the key for this.  I'm pretty sure it is for a Studebaker, having the stylized S on the flip, but not sure.  The chrome is good, not pitted, does have faint scratches in the chrome from the flip being moved.  Looks like chrome plating over diecast metal.  Under flip has no. 400 Wise Lock made in USA Cleveland Ohio.  Cap is 3 1/8 inches across front and back hole size for tank is 1 1/2 inches.  Ears are 1/4 inch wide by 1 7/8 long.  Not sure how old this is but would guess from maybe the 50's?  Selling cap with no key as is, no returns.  Pictures are part of the description and override my ramblings, any questions, ask.  Know what you are buying.