The High Voltage 255mah/25C pack from mylipo.de, a great upgrade for all 6mm and 7x16mm Whoops, as well as planes and helicopter with a single 8.0-8.5mm main motor.
Its safe to charge this pack to 4.35V, but it also performs great if you only charge it to 4.2V!

** shipping note **
- batteries from "US Warehouse" can only be shipped within US!
- batteries from "AU Warehouse" can only be shipped within Australia!

specs:

cell count: 1
nominal voltage: 3.8V
maximum voltage: 4.35V
capacity: 255mAh at 4.2V, 265mah @ 4.35V
continuous discharge rating: 25C
dimensions (incl. plug): 71mm x 11mm x 5.5mm
weight: 6.8g
plug: JST-PH-2.0