Sofa bed has to sit to lie, easy to pack characteristics, many families are essential in the living room, den or bedroom material bed. So, what should we pay attention to when buying a sofa bed it? & Nbsp; (1) moderately soft, elastic equilibrium. When lying is not a part of any feeling the weight of the body, the body will not be set in one place, but according to the body's natural forces, dispersed in various parts of the shoulders, hands, feet, buttocks and other. Good bed and a sofa bed will be like in bed will be installed inside the curved wooden slats spring-loaded, so that it can ensure the long-term body lying durable without deformation. Only plastic frame and foam as the main material of the sofa bed does not meet the body lying in the long-term, easily deformed, not suitable for purchase. & Nbsp; (2) pay attention to whether the four corners of the sound appears. Poor quality of the spring, at the corners of the most easy to find; good quality spring when under pressure is no sound. & Nbsp; (3) Note the location of the bed and the ground. The bed is too high, is not convenient to go to bed; the bed is too low, when the impact of sleep health, because dust tends to flow from the ground height of about 30 cm. Usually high 40 cm above the bed surface is better. & Nbsp; In addition, the fabric on the sofa bed is a certain stress, often with sofa bed cloth fabric-based, this type of fabric sofa bed is preferably subjected to pollution treatment, the future will be easier to clean up. Also note whether the cushion spring do support, but also in the spring above the mold and multi-density foam pad is filled, as long as this sofa bed will be soft, comfortable and durable.