It does its job, but it gave me a little trouble at first. A battery that had left me 6 months ago had a voltage of 5.5V and the charger did not charge it. It showed that it was damaged. However, when I jump-started the car with cables and it worked for about half an hour, the battery voltage rose to 12.3V (although the car couldn't start again when I turned it off) and then I tried charging it again. Everything was fine, it charged normally. It was ready in 12-13 hours. However, the charger should be able to do this job on its own with forced charging initially, instead of giving up. It says it charges batteries from 1V...
After 3-4 charges, the battery fully recovered. The rejuvenation brought back some cells that had gone out and the battery has the same power as before. In the first charge, the car started normally but the engine start-up was a bit sluggish.

The 55Ah battery was very depleted, at 10.3V, and it needed some time of pulse charging for rejuvenation. However, when it reached 11V and had a charge percentage indication above 20%, I asked it to continue with the high current of 4A but it refused. After a while, it started to heat up (despite it being winter) and the charging current dropped to 1A. After 24 hours, the battery had only reached 40%. It would have taken him days to complete. I continued with another charger.

Good charger, with a screen, low price, various protections, etc. It took almost 22 hours to charge 100% of a completely empty 44 Ah battery. Satisfied with the purchase.