H Ehanced by heat(no residues present) E or H(a) Enhanced by heat,residues insignificant(indication of very small residues within fissures only) E or H(b)Enhanced by heat,minor residuer are present(within fissures only) H(c)is a transitional grade between H(b) and H(d) 翻阅GRS证书上的原话哦~应该很权威了吧，表被无名资料欺骗