The SiMF4/1-7D1 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 3.5 to 4.5 GHz, Center Frequency 4 GHz, Insertion Loss 2.5 dB, Rejection 30 dB @3GHz&5.15GHz, 40 dB @2.8GHz&5.3GHz, 60 dB @DC~2GHz, 60 dB @6~10GHz, Upper Rejection 30 to 60 dB. Tags: Surface Mount, Cavity Filter. More details for SiMF4/1-7D1 can be seen below.