The TP-7 is a supersensitive microphone for telephone conferencing. Just plug it into the "MIC" jack of your recorder, and put the soft rubber-protected microphone side into your ear (the black side on the above picture).
During your call, the TP-7 will capture both sides of the conversation for recording on your voice recorder (digital recorders recommended). Frequency is 50 - 20,000 Hz.
It plugs into a 3.5 mm monaural jack and comes with 2 plug adapters to convert either to 3.5 mm stereo plug or to a 2.5 mm monaural plug.