Knot Types

Hair can be ventilated to poly base in 3 ways, v-looped, knotted and injected.

Knotted is the most durable way, V-looped and injected are more natural, because there is no visible knots, hair looks like growing out of scalp directly.

"Double reverse split knot" is used on lace mainly nowadays, it is strong and durable. 

However, it is a little big and visible for hairline. So we use "single knot" at hairline, which is small and neat. After bleaching knots, they become very invisible.