The PDBF-R21/R39-4C3 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 0.21 to 0.38 GHz, Center Frequency 0.3 GHz, Insertion Loss [email protected], Rejection =35 dB @80MHz & 600 MHz, Upper Rejection 35 dB. Tags: Surface Mount. More details for PDBF-R21/R39-4C3 can be seen below.