The SMI-3748 from Sierra Microwave Technology is a RF & Microwave Isolator with Frequency 3.7 to 4.8 GHz, Average Power Reverse 2 W, Insertion Loss 0.3 dB, Isolation 20 dB, Operating Temperature -20 to 65 Degree C. Tags: Module with Connector, Coaxial Isolator. More details for SMI-3748 can be seen below.