I have two Ten-Tec crystal filters for sale. These are 9 MHz, 8 pole crystal ladder filters that work in the Omni V, Omni VI, Omni (Series A, B,C), Argosy, Delta, Corsair and Orion I. #217 (500 Hz) $60 Shipped Priority Mail #218 (1.8 kHz) $60 Shipped Priority Mail Please respond off the forum. Paul, K5AF