What is the length and width of this bed?

2.00* 1.30*0.40 ? single bed

2.00* 1.50*0.40 ? single bed

2.00* 1.80*0.40 ? double bed

2.20*2.00*0.40 ? double bed

Mainly depends on where to put it and how big the room is to choose the size of the bed.

Why should the length, width and height of the bed be moderate?

For the bed itself, we should consider whether its length and width are enough, whether the bed body is flat, and whether it has good support and comfort. As for the height of the bed, it is generally appropriate to be slightly higher than the knee of the sleeper. It's hard to get up and down if it's too high. If it is too low, it is always inconvenient to bend over.