What are these small cylindrical parts? They are marked Daven 1030-G. They are 1-3/8 inch diameter and 1 inch high sealed aluminum cans with 13 solder terminals on one insulated end. The solder terminals are in pairs except one marked "C" (for common I assume). The six terminal pairs are marked 1, 2, 3, 4, 10, 20. What are these? 73, Don Merz, N3RHT