I had bought two Tru-Nords already so I gave the Marbles replacement to my father. So far so good. I think that the oil is some sort of mineral oil. I took the old broken one and drilled a 1/16" hole in the casing to see if it would work as a dry compass. It didn't. <img src="/images/graemlins/grin.gif" alt="" />

Regards, VInce