Antique Earphones [Restoration]

I restore these ~100 year old earphones so that they work with modern equipment. These earphones are most likely around 100 years old as the patents were filed in 1923. This restoration was on a pair of C. Brandes Inc. earphones. You can have a look at the original product catalog from 1916 here: These sold for around the equivalent of $150USD in 2019 and all patents can be found under Dietrich Frederick. I was really exci