The 4MB/C-138/U20-S5 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 127.1 to 148.9 MHz, Bandwidth 21.8 MHz (1dB), Center Frequency 138 MHz, Insertion Loss 1.89 dB, Upper Rejection 40 dB. Tags: Lumped Component Filter. More details for 4MB/C-138/U20-S5 can be seen below.