The difference between Full HD lace and double lace lies in their construction. Full HD lace involves using high-definition lace for the entire base, providing a seamless and natural appearance. On the other hand, double lace typically refers to a wig with two layers of lace. While both aim for a natural and comfortable look, Full HD lace emphasizes a more refined and undetectable finish, while the Double Lace offers enhanced durability by providing extra reinforcement.