The 3MB/C-21.4/U4-14 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 18.885 to 23.915 MHz, Bandwidth 5.03 MHz (1dB), Center Frequency 21.4 MHz, Insertion Loss 0.65 dB, Upper Rejection 40 dB. Tags: Lumped Component Filter. More details for 3MB/C-21.4/U4-14 can be seen below.