The ECS-96SMF21A30 from ECS Inc. International is a Band Pass Filter with Frequency 21.385 to 21.415 MHz, Bandwidth 15 kHz, Center Frequency 21.4 MHz, Insertion Loss 2 dB, Rejection 70 dB. Tags: Surface Mount, Crystal Filter. More details for ECS-96SMF21A30 can be seen below.