Greetings, I have these filters for sale: 282 - 250 Hz, 6.3 MHz 285 - 500 Hz, 6.3 MHz 288 - 1.8 KHz, 6.3 MHz $55 each or $150 for all three shipped USPS Priority, CONUS Model 257 Voice Synthesizer $50 shipped USPS Priority, CONUS Thank you for reading. 73, Dalton W4PJV