3 d is convenient, no need to turn the level around. The rays are quite clear, the attached photos and videos were taken on a sunny day, although there is no sun in the room, it is well lit. The line on the curtain is visible even against the background of a lighted window. In the photo with a beam thickness of 1 mm, the level is at a distance of 0.5 m, with a beam thickness of 2 mm, the level is at a distance of 6 m. When buying, I tested it, the error of my copy along the horizon is 1 mm per 10 m. This is the easiest and most accurate test. I tested the vertical error very conditionally, it is possible to determine it in an apartment with ceilings of 2.50 only with a strong deviation from the norm, but at least for this case a test in an apartment is needed. For accurate verification, you need a height of at least 5-10 m. To check the correspondence of right angles between the beams, you need a lot of free space, it is convenient to measure 3m x 4m, then the diagonal will be 5m, I measured this parameter at shorter lengths after purchase, there are no gross deviations , and more precisely in apartment conditions it is difficult to measure. The remote control is convenient, it works in the apartment without a retractable antenna, obviously the antenna will come in handy at a long distance. The pendulum, if you swing as much as possible, calms down in 4 seconds. Nice, fabric-lined semi-rigid case. When one battery is in the level, there is enough space in the case to put another device in it, I put the rangefinder in the case (140x65x35).