The BT-218 from American Microwave Corporation is a Bias Tee with Frequency 10 MHz to 20 GHz, Max. Voltage 50 V, Max Current 30 mA (0 to 0.03 A), Insertion Loss 1 to 1.5 dB, Isolation 20 to 30 dB. Tags: Module with Connector. More details for BT-218 can be seen below.