This range of microphone extension cables are for use with the Optimus range of sound level meters. They allow the sound level measurement microphone to be positioned away from the meter.
Only correctly designed and produced microphone extension cables should be used to ensure the measurement chain continues to meet the strict international sound level meter standards.
The ZL2xx microphone extension cables fit between the meter top and the preamplifier. The preamplifier is at the end of the extension cable (as opposed to on the meter body) so that an amplified signal is passed through the cable, giving better immunity to electrical noise.
Each end of the cable connects with a threaded ring to ensure a reliable connection.