1967 to 1969 Barracuda locking gas cap

I have never installed mine and I can't get to the car yet but this is the auction description.

"NOS MoPar #2925881 locking gas cap for 1967, 1968, and 1969 Plymouth Barracuda, Cuda, and 1968, 1969, and 1970 Dodge Charger models including R/T and SE. This is the chromed cap that goes down inside the filler neck, and under the racing style "flip top" FUEL cap. Put this finishing touch on your restoration and wait for the judges to go. WoW! When only NOS MoPar will do.......... "

http://www.ebay.com/itm/1967-1968-1...Parts_Accessories&hash=item5d343e706e&vxp=mtr