What is the ceiling height? Is the size fixed?

The size of the ceiling should be 20 centimeters high from the wall point a class, 30 or 35 from the wall width, there are also a few 40 centimeters of the light slot, the baffle outside the baffle width is generally in about 8 centimeters, the light slot width of 10 centimeters or 12 centimeters, generally based on the width of the entire ceiling to decide, the ceiling height is high, the high fork will be larger, the ceiling height is relatively low height difference will be smaller.