The 4FS10-1638/U16-O/O from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 1625.5 to 1650.5 MHz, Bandwidth 25 MHz (1dB), Center Frequency 1638 MHz, Insertion Loss 0.6 dB, Upper Rejection 50 dB. Tags: Cavity Filter. More details for 4FS10-1638/U16-O/O can be seen below.