The 2937 from KR Electronics (A Division of NIC) is a Low Pass RF Filter with Frequency DC to 20 MHz, Stopband Frequency 44.1 MHz, 3 dB Cutoff Frequency 20 MHz, Lower Rejection 45 [email protected] MHz, Upper Rejection 3 [email protected] MHz. Tags: Module with Connector. More details for 2937 can be seen below.