The XLF-551+ from Mini Circuits is a Low Pass RF Filter with Frequency DC to 0.55 GHz, Stopband Frequency 1.14 to 18.5 GHz, 3 dB Cutoff Frequency 0.77 GHz, Insertion Loss 1.4 to 1.8 dB, Rejection 12 to 24 dB. Tags: Surface Mount, Reflectionless Filter. More details for XLF-551+ can be seen below.