This is T-Connector – JST Female in-line power adapter. It features 1 male T-Connector to 1 female T-Connector with a JST Female plug lead connected in parallel.

Use this adapter to power a stand-alone BEC, an electronic accessory such as a cooling fan, LED lights, etc. Be aware of the voltage limits of the device you connect to the JST plug lead to make sure that it can handle the voltage of the main battery connected to this adapter.