We use very fine baby hair to cover the front of our lace front closures, which are 4 inches wide by 4 inches deep. This enables the person to cover the area below the hairline up to a depth of 4 inches and use lace closure for a tiny front hairline if necessary.

Lace closure(https://www.mscocohair.com/blog/post/lace-closure-against-lace-frontal/)