Usually, I am very lenient, especially with cheap equipment. However, with this particular instrument, I rarely received accurate measurements. I don't know why: I can't believe that all devices of this model are useless. Maybe, I got a defective product. Definitely, though, I will not try my luck with this again.

For its price, it is good. It measures internal spaces and has memory. The negative is that it does not measure small distances below 0.50m and that it operates with a special battery and not the classic ones. It has functions that will help many. Good for beginners

He did not calculate correctly even half of the distances I wanted (very large deviations)! Very bad purchase.
Also, the laser that shows the point up to which it measures was not aligned with the device!

I bought it, read my friend's review, and got scared, so I decided not to measure internal walls and non-permeable surfaces. In the end, I measured everything easily, both nearby and far away. There is no laser concept; the job is done with ultrasound, so it sends sound and receives a response from the opposite obstacle. However, it also has a laser pointer so you know what you're looking at. I bow down to the technology that gives you accurate area measurements with its two memories, and with the third memory, you can also request volume measurements. People didn't like the batteries that should not be left in the devices unless they are constantly used, like a remote control, with minimal power consumption, and kept at a good temperature and conductivity at the ends. In the case of a 9-volt battery, they are stored separately in an airtight nylon bag. Don't buy a 5 euro battery; the scrubber costs 60 cents, and if you're in a hurry, go to a convenience store for 2 euros.

Completely useless, in order for it to work you have to take out and put back the battery after it has "rested" for about 8 hours.

It is very good and reliable. It would be more convenient if it had one or two levels on it.
However, it is reliable and for its price, I think it is a good investment.