The L288XC3S from Knowles is a Low Pass RF Filter with Frequency DC to 27 GHz, Stopband Frequency 34 to 50 GHz, 3 dB Cutoff Frequency 28.8 GHz, Insertion Loss 1.5 to 1.75 dB, Rejection 40 to 45 dB. Tags: Surface Mount. More details for L288XC3S can be seen below.