The XLF-551-D+ 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 dB, Rejection 15 to 24 dB. Tags: Die, Reflectionless Filter. More details for XLF-551-D+ can be seen below.