I found I could order one from GIVI, $22 plus shipping and then the cost of cutting it. I cheated and made a brass key blank and had it cut at an ACE Hdwr. store. It works on one side but not the other, doesn’t matter as I can leave it in place and open/close the trunk without digging for a key. A bol;t holds the trunk to the rack so it can’t be stolen. I’m a happy camper.