The SiMF28R5/5-5W2 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 25.6 to 31 GHz, Center Frequency 28.5 GHz, Insertion Loss 1.1 dB, Rejection 20 dB @23.5GHz&37GHz, 40 dB @22.27GHz, 60 dB @DC~8.9GHz, Upper Rejection 20 to 40 dB. Tags: Surface Mount, Cavity Filter. More details for SiMF28R5/5-5W2 can be seen below.