Ruko has already paid off
The ruko device has already saved me once when a faulty battery in the drone died 10 minutes into a flight but the ruko helped me track it to the foot in a tall grass feild of grass that i would have never found without it. Device and app work fine but buzzer could be way louder. Maybe its just me but both my devices ONLY charge with supplied cable and no other and not sure why, sure hope I never loose its supplied cable. Overall very good option