The 991-370420-301 from M2 Global Technology is a Drop-In Isolator that operates from 3.7 GHz to 4.2 GHz. It provides isolation of 20 dB and has an insertion loss of 0.4 dB. The isolator can handle a forward power up to 20 Watts and a reverse power of up to 10 Watts. It is available in a Drop-In Package and measures 0.75 x 0.75 Inches.