HD is the abbreviation of high definition. People apply it to human hair wigs to make the lace part invisible and undetectable when applied to the scalp. It is a lace material that used to be called Swiss lace. It can along the hairline, people hardly can notice it after wearing HD Lace Wigs.   According to the lace area used on the wig, HD lace wigs mainly include 13x4 HD lace wigs, 13x6...