The 2586-40 from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 40 MHz, Stopband Frequency 80 MHz, 3 dB Cutoff Frequency 40 MHz, Lower Rejection 55 dB@80 MHz, Upper Rejection 0.5 dB@80 MHz. Tags: Module with Connector. More details for 2586-40 can be seen below.