The CU4S0401BT-1542-00 from TDK is a RF & Microwave Isolator with Frequency 1.525 to 1.559 GHz, Bandwidth 34 MHz, Average Power Forward 2.5 W, Average Power Reverse 0.6 W, Insertion Loss 0.7 dB. Tags: Surface Mount, Surface Mount Isolator. More details for CU4S0401BT-1542-00 can be seen below.