PU refers to the type of material that hair strands are sewn onto. PU material is a thin gauze-like, nearly transparent material. It is more natural skin look and totally undetectable.
Skin weft extensions are seamless without bumps when applied properly.
Skin weft can be attached into your parted hair using double sided tape ( not included) . It gives the appearance of hair growing from your own scalp. It is mainly used in the front part of one head or to close a weave. You certainly can use it anyway you would like , even to do your entire head. You can use this as bulk hair or tip it for single strand.