I need 2 xtal ovens for my pair of ARR-41s. These are the ones used in the calibrator. I have 12 volt ovens to swap, or will buy, if the heaters are OK, Not open. (I have the 500Khz xtals, but the oven heaters are open) Thanks, John Allen, W4GQT since 1959. My address is good in QRZ.