The B138LA2S from Knowles is a Band Pass Filter with Frequency 13.5 to 14 GHz, Bandwidth 500 MHz, Center Frequency 13.75 GHz, Insertion Loss 2.75 to 3.25 dB, Rejection 40 to 45 dB. Tags: Surface Mount, Ceramic Filter. More details for B138LA2S can be seen below.