Six batteries are required to power the handset controller. The controller charges the battery on board the mosquito.
Pros. Once out of the box and charged the mosquito flew immediately.
Cons. While straight up and straight down presented no problems the direction in which the mosquito flew seemed to be a matter of chance rather than fine control.
When, rather than if, the mosquito crashes the rotors are automatically switched off. The rotors are quite frail and a succession of hard knocks may well fracture them.
The control box switch should be set back to zero (no power) as soon as the mosquito appears to be heading for a crash in order to avoid rotor damage.