A.800kg/m3 B.800~1400kg/m3 C.1400~1900kg/m3 D.1900kg/m3
A.3.25 B.3.75 C.4.25 D.4.75
A.3.7~3.1 B.2.2~1.6 C.3.0~2.3 D.2.3~1.6