I repair phones every day, so I know perfectly well that in the service business, the stability of spare parts decides everything. I mainly work with iPhones, when I change batteries, I put DEJI Battery with lithium-ion cells of class A+. The main advantage is increased capacity and increased resource, they support fast charging and have protection against short circuits and overcharging. The system sees the battery as native, there is no need to flash anything. All international certificates such as CE or RoHS are in place, so the smartphone works stably, which significantly reduces the percentage of returns.