From Muchmore Racing:
Using LiHV-compatible chargers a 2S pack can be charged up to 8.7V allowing for the higher output voltage. LiHV packs are also good to be charged to the standard 8.4V for sanctioned races with the flat discharge curve compared to regular packs making for more punch towards the end of a run.
Voltage Input: 7.6V
Dimensions (LxWxH): 138.5 x 46.5 x 22.3mm