1. Look at the flatness: the smaller the gap between the two tiles, the more uniform it is, which means the better the flatness. The diagonal error of the tiles should not be greater than 1 mm!

2. Look at the stain resistance: use an oil-based pen to write, do not use a water-based pen, and wait for a few minutes to wipe it clean, indicating that the seed surface has good stain resistance

3. Look at the anti-skid property: lay the tiles flat and pour a little water, and rub them back and forth with your feet. If there is astringent feeling on the feet, it means that the anti-skid property is good.

4. Listen to the sound: Tap the tile with a hard object to listen to it. The better the effect of the tile, the clearer the sound. Or hold the corner of the tile with your left hand, hang down naturally, and then lightly tap the tile with your right hand. If the sound is clear and melodious, it is the top grade, and if the sound is dull, it is the low grade.

5. Test by pouring water on the back of the tile. If the water disperses faster, it proves that the density is sparse, and the slower the water disperses, it proves that the tile has a higher density and better quality.