Etronix JST in Series Cable ET0702 Male two female connectors Y harness splitter

Additional Information -

Etronix JST In Series Cable ET0702

In RC (Radio Control) applications, a JST in series lead, also known as a JST Y-harness or a JST splitter, is used to connect two batteries in series to increase the voltage of the power source, while keeping the current draw relatively the same as from a single battery. This is commonly done with LiPo batteries to power systems that require a higher voltage than a single battery can provide.

Alternative Y lead you maybe looking for is ET0701