The SiMF21/2-7D2 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 20 to 22 GHz, Center Frequency 21 GHz, Insertion Loss 2 dB, Rejection 30 dB @18.5GHz&23.1GHz, 40 dB @18.2GHz&23.3GHz, 60 dB @DC~14.5GHz, 50 dB @23.5~27GHz, Upper Rejection 30 to 50 dB. Tags: Surface Mount, Cavity Filter. More details for SiMF21/2-7D2 can be seen below.