Monofilent ... not good for a front hairline unless u wearin ur hair forward, Some people like it for the base, but I think lace is a lot better.. its lighter and feels nicer.. Some claim it is good for the base tho.. something about more area to tie knots and some monofilents do a goodjob of hiding knots etc.. it lasts longer and is extremely durable.> but its heavier, thicker and not as comfortable.