When making the transition from BSS (Beauty Supply Store) Hair to purchasing virgin hair from a vendor. One of the first questions I'm often asked "Hair comes in "packs"! Why is this vendor talking about ounces?
Vendors sell hair by the ounce. In most cases vendors sell hair in "bundles" containing 3.6oz -4oz (most sell in 4oz bundles).
The formula is actually quite simple (I run from math so if I say its easy then it really is).
1 Pack of BSS Hair = 1 bundle of hair from a vendor.
So if you use 2 packs, order two 4oz. bundles= 8oz.
If your flirting with 18" or longer order 3 bundles order 12oz. or 3 bundles. Longer length wefts are usually shorter in width with because the hair is longer and weighs a little more.
Hope that helps.. If your a newbie and have question feel free to leave them in the comments or contact me on Facebook or Twitter and I will do my best to answer your question. I wish that I knew what I know now when I first started dealing with hair vendors and extensions in general.