The 2961-SMA from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 300 MHz, Stopband Frequency 500 MHz, 3 dB Cutoff Frequency 300 MHz, Lower Rejection 40 dB@500 MHz, Upper Rejection 1 dB@500 MHz. Tags: Module with Connector. More details for 2961-SMA can be seen below.