The 2484 from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 20 kHz, Stopband Frequency 21 KHz, 3 dB Cutoff Frequency 20 kHz, Lower Rejection 12 dB@21 KHz, Upper Rejection 1.5 dB@21 KHz. Tags: Module with Connector. More details for 2484 can be seen below.