Can you id this controller

[passpato]

Can anyone tell me what controller I have here? Im working on a friends ebike. He says he bought it new a year ago. Its a Carrera mountain bike with a rear wheel ebike kit fitted. The bike has a uk3 5 digital screen on the handlebars and it looks like the speed controller has been replaced but I'm not sure. The battery voltage measures 50v so its a 48v system. I don't know the wattage of the motor and there is no makers name on its casing. Unfortunately I didn't take a photo of the motor before returning the bike. Does anyone know about this bike. He was complaining about the motor cutting in and out or spluttering but its not doing it now.