This adapter cable can be used for converting the larger 120SR / QM / JST plug batteries into the smaller mCP-X plug to get longer flight times.
You finally could answer the old problem - how will my mCP-X fly with my 120 SR's battery.
Convert the 120SR / mQX / JST plugged batteries into the smaller mCP-X plug
JST to PH 2P 22awg 5cm Soft Silicone Wire