The 991-420440-901 from M2 Global Technology is a RF & Microwave Isolator with Frequency 4.2 to 4.4 GHz, Average Power Forward 60 W, Average Power Reverse 10 W, Insertion Loss 0.05 dB, Isolation 20 dB. Tags: Drop-In, Drop-In Isolator. More details for 991-420440-901 can be seen below.