need 101 for synth

Which is best depends on what you want the hair to do. 

If you need to style your hair with a straightening or curling iron every day then you probably want a thermal like Wawa or Ebonyline or Hot Stuff Fusion.
If you need hair that has some curl/wave to it to begin with but won't need to survive heavy appliance use PH has a huge range of colors and can be ordered in practically anycurl you want if you can wait for a special or der or comes standard in Straight, 50mm wave, and 28mm curl.
Other monofibres (plastikhaar is a monofibre) like Dome, Trimco, Prostyles may have slight advantages or disadvantages over PH I don't know.

If you wash your hair (particularly in the case of PH/mono) in cool water rather than hot you can avoid losing the curl quickly.  Even if you do lose it in the  mono's it can be put back.  You can use a curling iron on it but you have to be more careful.

The numbers?  As in color numbers or 50mm, 28mm?
1 = Jet Black
1b = Off Black
2 = Very Dark brown
4 = Dark brown
613 = Light/platinum blond.

OR 50mm is hair that the diameter of the curl is 50mm.  ~ 2 inches  uner its own weight it is curly like that at the ends and wavy headed to straight as you go higher up
28mm has a curl of diameter 28mm 1 1/8"

Lots of people like combinations of different synths say PH in the back and thermal in front.

Ask more speciffic questions I shall try to provide more speciffic answers

PH curl sizes (thanks to JENNY who found it on that maze of a website!):
http://www.plastikhaar.ch/bilder/curls.jpg

Marie, if your weft sheds - Bohyme or any other - put superglue along the weft before you install it (let it dry first). That's almost a given with wefts. They shed like a big dog or small fuzzy cat.

As far as colors...girl, welcome to the club. It's all about research. You should see the BOXES of hair I have of all types - synth, hh, straight, curly, wavy...and all in the dark browns like you. The most beautiful colors I loved the most - a real deep coffee brown and a gorgeous REAL chocolate - was by Trimco, but I don't like the texture of the hair. But...it's a standard by which I judge other hair's colors.

My suggestion is to go back and read lots and lots of posts on the board (it takes days). You'll learn a LOT and give yourself time to figure out what you want, what's out there, what's been done...

The long and winding road.

Thank's guy's !  at least ordering this and getting a wrong color wont result in my morgatge being late!!!! My sheding happend when I used latex and coated it with nail glue for shrinky install. Now I'm using epoxy no shedding this stuff is strong!!! I can't wait to try synth.. Allthough a client of mine with virgin hair my color let me keep the 10 to 12 inch pony I sniped off her!! I wish it was a tad longer its soooo soft.