These JST-XH Wire Extension 15cm is widely used to connect lipo battery, especially for RC helicopter, Rc Airplane, Rc Cars, Racing Rc Quadcopter, and Multirotors.
This Extension Lead is for connecting the Lipo Balance Lead to your charger, making it much easier to connect because the balance lead on the lipo battery is much shorter than the charging lead.
The pitch for these connectors is 2.0mm.