This Nye Viking Model 020-001 50 ohm low pass filter has over 65 dB of attenuation above 57 Mhz to help keep your HF transmitter harmonics out of local television receivers.
Comes with 2 UHF SO-239 female connectors to go between your HF transceiver and antenna.
See https://www.universal-radio.com/catalog//hamacc/2018.html
Asking $30 CAD, plus shipping outside the Calgary area.
If interested please email me at nrossairdrie at shaw.ca Mike VE6TC