HB

Flame-retardant grades that pass the resin horizontal combustion test based on the flame-retardant UL94 standard are certified. The thickness (mainly the minimum thickness) of the material when manufactured is specified. The flame-retardant grade is lower than that of V0 material (There are grades V1 and V2 between HB and V0, but they are not often used. Flame-retardant resin can be divided into HB and V0. many). UL standards on the product side specify the resin grades that can be used.