The 12-18” full volume extension is the piece in our collection , its is Long, thick and luxurious, the full volume extension is 18 inches in length with 12” layers. The mono top base is approximately 5”x 6”, or larger. which gives this hairpiece twice the density of the 12-16” root coverage. We offer any customize color requested.. This hairpiece is worn for maximum volume, length and fullness. It is sufficiently large enough to cover any thinning spots on the sides and top of the head as well as the crown and back of the head.