Single drawn looks more natural and it's cheaper. Double drawn looks way thicker when installed and will be more expensive to purchase.
I had that backwards. Here's a good FAQ I found on goddessofhair.com, It pretty much answers all the OP's questions.
Frequently Asked Questions
What are hair extensions?
Hair Extensions is the term used when you fuse, lock, weave, braid or bond human or synthetic hair to your own. Hair Extensions are considered semi-permanent, as opposed to say a wig, which you can take off at night. Clip-in extensions can be taken off at night, but are still considered extensions.
A Lot of Sites Say 100% Human Hair, and Virgin Remi, What does all this Mean?
Human hair is the most often sought out, because it looks the most natural, however not all human hair is the same. There is very cheap, non-cuticle hair that will dry out after one wash and is a relative waste of money. This hair is typicall Chinese and may say 'Remy" on the pack, but will be a non-cuticle hair drayed with a silicon that will tangle after 3-4 washes.There are so many other companies on the internet claiming ‘virgin’ hair for many hundreds of dollars, when what they really have is nice quality European hair that has been dyed and processed, therefore not virgin. True virgin hair has never been dyed or chemically altered, so you can only get it in the shades it comes in-for Virgin Russian hair, mostly medium browns-which doesn’t make it very viable to sell online unless you buy in bulk. The hair is virgin and is either single drawn or double drawn. Single drawn hair is cheaper, but has the normal look of breakage and shorter hairs, double drawn means every single hair in your bundle is exactly the same length, and looks healthier and glossier. It’s also much more expensive. Remi or cuticle hair means that the healthy covering of the hair shaft hasn’t been stripped to bleach and dye the hair in a cheaper way, which lengthens the life and reusability of the hair to a year or more.
At Goddess Hair, we recommend Indian cuticle hair (Our 'Deira™ line) of Indian and Chinese double drawn Indian or Chinese Remi because we work directly with our own manufacturer and are very specific about the quality we get. We are experts in the extensions field, and have thousands of clients because of our insistence to receiving quality hair.
What is the Difference Between Hand-Tied, Bulk and Weft Hair?
A weft of hair is hair that is folded and sewn for easy application in weaving and other track applications like braided tracks, bonded tracks or taped tracks. The hair can also be cut from the weft into smaller pieces for custom tracks or tiny pieces (20 hairs or less) and tipped with a hot adhesive like keratin for a strand by strand method like fusion or locs. Hand-tied hair means the sewn seam is very tiny and looks better on people with thinner hair. Bulk hair has the look of a cut ponytail, and has to be handled carefully so that the hair lengths stay even.
How are extensions applied?
Fusion (Strand by Strand)- This is a process done strand by strand in even rows (if done properly) leaving a generous perimeter, so bonds don’t show. Using a variety of adhesives and heating elements (like fusion irons made for hair extensions), extension hair is added directly to your own hair. Hair can be bought already cut, weft removed and pre tipped with adhesive. This is approximately 3 times the cost of buying the hair in bulk or on the weft, and is usually tipped in a keratin substance we don’t recommend fusing with due to difficulty in removal. Your own hair must lie over the very top of the bonds for a natural look. Fusion is ideal for those with thin hair or hair on the drier side. Goddess Locs (Strand by Strand) are similar to Fusion. Locs are applied in even rows leaving a generous perimeter, although locs aren’t as invisible as fusion, so more hair may need to be left out to cover. Using the Goddess Loc Loader, hair is looped through and into the loc. Use the color of loc that matches the hair root color the closest..
Weaving - This is a process in which you create a corn row or track around the head and close to the scalp. Extension hair in hand tied wefts or regular wefts are sewn on the braids. Your own hair lays over the tracks for a natural look. (click here for supplies)
Hair Taping - This is the hottest new hair extension on the market! You simply pin up your hair in several sections, peel and add the desired length of wefted or hand tied hair to the proflex tape, press firmly, and pull down your own hair to secure. Easy to do yourself. It lasts for several days to a month, and is excellent for weddings, Vegas trips, or a fun night out.
What What Color Do I Choose For My Hair? Can I See a Color Chart?
Internet Colors are very inaccurate, but if you are in a hurry, go to your local wig supply and ask to see a color ring. We will do our best to match it. When choosing a color to match your own hair, choose a color that matches your hair from the middle to the ends. Never buy hair the color at your roots as that is always darker. The blending of your hair on the bottom part is the most important, but you can also do color blending with several shades. We sell color rings in both Bohyme and our hair replacement systems so you can get an exact match. Bohyme hair comes in many beautiful shades to choose from.
How much hair do I need?
Ladies with thin to medium hair wear ¼ pound, or one bag. However, you may need more than 1/4 pound if:
1)Your hair is thick
2)You have heavy layers or a 'bob' cut
3)You are wearing 22" length or longer
Because hair comes by the ¼ pound, when you order longer hair, you get more hair in length than in the thickness so you will more than ¼ pound to make it thicker.