Having purchased an AnyTone AT-600 Turbo for GSM calls some time ago, I needed to upgrade it to a 800/900 MHz bi-band booster in order to improve not only GSM calls but 4G internet as well. The customer service team helped me find the compatible booster supporting 800 / 900Mhz. It was the Nikrans LCD600-GSM + 4G which is much more powerful than my old AnyTone booster. I got very satisfactory results.
As you can see from the pictures, the LCD600-GSM + 4G is connected through a transformer 220V / 110V as to never exceed 240 V. This recommendation that had been made before and that I found it quite wise. The signal at the external antenna is quite low at my home, but I found a way out: I put the antenna Yagi T through a wall of 80cm by a small skylight window) but it does not cause any signal loss, since the amp is very powerful and everything works very well with this Yagi.
The power of the amplifier is excellent. While the AT600 turbo was amplifying only 2 meters away from the indoor antenna, now I have a very good signal even with the indoor antenna hidden behind a 50cm stone wall. It is a very appreciable point. Therefore, the booster LCD600-GSM + 4G at LTE 800Mhz suits me very well. I receive the Orange 4G at 800Mhz which is present at the moment in my region.