The XLF-421+ from Mini Circuits is a Low Pass RF Filter with Frequency DC to 0.42 GHz, Stopband Frequency 900 MHz to 18 GHz, 3 dB Cutoff Frequency 0.61 GHz, Insertion Loss 1.4 to 1.8 dB, Rejection 11 to 24 dB. Tags: Surface Mount, Reflectionless Filter. More details for XLF-421+ can be seen below.