Ten Tec 218 still available, others are gone. 73 Bob K4LW Buying a used Orion at the Ten Tec sale? I have the following roofing filters for sale: Inrad 760 250 Hz Inrad 759 400 Hz Inrad 762 600 Hz Ten Tec 218 1.8 kHz $60 each, shipped in US. Bob K4LW