The AM21.4CR210 from Anatech Electronics is a Band Pass Filter with Frequency 19.9 to 22.9 MHz, Bandwidth 3 MHz, Center Frequency 21.4 MHz, Insertion Loss 3.0 dB, Lower Rejection 40 dB at Fc +/- 6 MHz. Tags: Surface Mount, Crystal Filter. More details for AM21.4CR210 can be seen below.