The 2987 from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 350 MHz, Stopband Frequency 580 MHz, 3 dB Cutoff Frequency 350 MHz, Lower Rejection 60 dB@580 MHz, Upper Rejection 1 dB@580 MHz. Tags: Module with Connector. More details for 2987 can be seen below.