CEM1 (or CEM-1) which stands for Composite epoxy material, is a low-cost, flame-retardant, cellulose-paper-based laminate with only one layer of woven glass fabric.
CEM1 material is not transparent, and it is low-grade material.
CEM1 is milky white material.
CEM-1 is also available in grey and yellow shades.
To control the production cost, the designer prefers to use cem1 material.