The DMCF21D006-21.40MHz from Dynamic Engineers is a Band Pass Filter with Frequency 21.394 to 21.406 MHz, Bandwidth 12 kHz, Center Frequency 21.4 MHz, Insertion Loss 3.5 dB, Rejection 60 dB@±14 kHz to 90 dB@±20 kHz of Center Frequency. Tags: Surface Mount, Through Hole, Crystal Filter. More details for DMCF21D006-21.40MHz can be seen below.