The 3274-BNC-TNC from KR Electronics is a band pass filter with a centre frequency of 428 MHz and 3dB bandwidth of 40 MHz. The filter has an insertion loss of under 5 dB and a rejection of over 40 dB. It is available in a module that measures 3.5 x 1.5 x 0.7 inches with BNC or TNC connectors. The filter is specially designed to pass a DC current from the input to output. Other center frequencies and bandwidths are available.