From owner of guitar: I would appreciate knowledge shared on what type and size tension-bar wrench is used for this model guitar, circa unknown. The local hardware store might have a match if I learn size/type. Retailers as well as Ovation (at least, in my search) do not carry parts nor this basic accessory. Nothing on Amazon nor eBay presently noted for this guitar. I've learned that different guitars use trust-bar wrenches either of a regular type of hex head or having a ball-like end on a hex head--I don't want to strip the trust rod with wrong type/size. (I cannot see mine as it is adjusted from inside body.) Gratefully appreciated of time read, Jeff.