The 2820-18.7 from KR Electronics (A Division of NIC) is a Band Pass Filter with Frequency 15.45 to 21.95 MHz, Bandwidth 6.5 MHz, Center Frequency 18.7 MHz, Insertion Loss 3 dB, Rejection 60 dB. Tags: Surface Mount, Lumped Component Filter. More details for 2820-18.7 can be seen below.