The U839 from UDI RC Toys is a super mini size quadcopter, having the smallest volume and the lightest weight and featuring strong stability and operability beyond imagination.
You watched a night flight with the UDI U839 Nano quadcopter.
You can read more about the UDI U839 Nano quadcopter here on firstquadcopter.com.
The UDI U839 Nano is my first RC aircraft.
I find it a little hard to control but, I’ve only played with it for a few hours so far.