The L157XF3W from Knowles is a Low Pass RF Filter with Frequency DC to 15 GHz, Stopband Frequency 20.5 to 29.5 GHz, 3 dB Cutoff Frequency 15.7 GHz, Insertion Loss 1.5 to 3 dB, Rejection 30 dB. Tags: Surface Mount, Ceramic Filter. More details for L157XF3W can be seen below.