The 2928 from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 0.1 MHz, Stopband Frequency 140 KHz, 3 dB Cutoff Frequency 0.1 MHz, Lower Rejection 45 dB@140 KHz, Upper Rejection 1 dB@140 KHz. Tags: Module with Connector. More details for 2928 can be seen below.