Here’s some info about what to expect in a basic set of natural white wool tzitzit strings.

Dimensions
Length of main strings: 1 yd (36″)
Length of shamash strings: 2 yd (72″)
Total length: 20 yd (12 main strings, 4 shamash strings)
Thickness: 16-18 WPI
Ply: 2
Fiber info
Wool type: 18-20 micron merino wool
Wool source: NH, ME, NY, or WI farms

Variations
Some colors use 20-22 micron merino, corriedale, falkland, or shepherdess wool instead, from various farms around the US.
Gradient colors are 3-ply (chain plied), to create the shifting color effect.
Many of these parameters can be changed for a custom order! Let me know what you’d like, and I’ll do my best to make it happen. :^)