This unit is a side part closure unit, closure is 4x4 and placed off to the side that allows for a side part as shown in the photo.
 
The denistiy on this lace wig is 200% (standard is typically 120%) . The cap size is large.  4 full bundles with a closure was used to construct this unit - lots of hair!  This unit was hand made by a local stylist.  Hair color is 1B. Actual unit in the photograph.
 
Units are an excellent investment, for not much more than the price of the hair itself you recieve a high quality unit that can last years.  Yes you may sew these down if desired.  Rather than paying the full price of a sew in you can have someone simply braid you up and sew this down for under $50 depending on who you go to for your hair service!