Hi- I have a Vibroplex bug that I will swap for a 500 Hz and a 250 Hz Ten Tec crystal filters. Numbers 282, 285 6.3 MHz filters and 216 and 217 9MHz filters will work. The Vibroplex is in excellent condition. The base is chrome, NewYork manufacture with 1962 serial number: 23002*. I can supply pictures if you are interested. 73 de Dave in NH