Review on 🚲 TOTMOX - Acera RD-M390 Rear Derailleur for 7-9 Speed MTB Bikes by Joel Miranda

He looked decent. Clearly a copy of a Shimano derailleur. After installing and configuring it seemed to work fine, copy or not. After a day or two the switch was off and had to be reset. It was noticed that the lower swing arm was slightly bent, which affected the shifting. Tried to bend back into shape and it felt like it was made out of tin foil. "You get what you pay for": Most of the plastic components and spring mechanics are fine, but the metal used is not good.