The ECS-96SMF21A15 from ECS Inc. International is a Band Pass Filter with Frequency 21.392 to 21.407 MHz, Bandwidth 7.5 kHz, Center Frequency 21.4 MHz, Insertion Loss 2 dB, Rejection 70 dB. Tags: Surface Mount, Crystal Filter. More details for ECS-96SMF21A15 can be seen below.