In this post we'll be comparing different types of all-white tzitzit strings in terms of length, thickness and quality.

Until around 15 years ago, tzitzit strings came in just thin or thick. Then many manufacturers introduced medium.

I'd say there's a fourth type, extra thick. But the thing is, they're not labeled as such. However, it's plain to see that Mishkan Hatchelet makes their "thick" strings considerable thicker than the other brands.

Thickness is not standardized. Therefore one company's "medium" might be just slightly thicker than another company's "thin." The "medium" made by Mishkan Hatchelet is just slightly thinner than some companies' "thick," and could pass for thick. 

The length generally correlates with thickness. Standard tzitzit length is as follows:

• Thin - 50 cm
• Medium 55 cm
• Thick 60 cm

Most of the manufacturers also make extra long versions, e.g. medium 65 cm, thick 70 and thick 80 cm (and occasionally even 90 cm strings).

This refers to the length of the strings when doubled. For example, a packet of thin strings typically has three 100 cm long strings for each corner, plus one extra long shamash string. When you insert the string and tie the first double knot, you'll have around 44 cm from the double knot at the edge of the tallit, to the tips of the strings. By the time you're finished tying, that will probably contract to 30-35 cm, depending on the tying custom and how tightly you tie. The minimum overall length from the start of the first knot to the tips is 24 cm according to the Grach Naeh, and 30 cm according to the Chazon Ish. 

Aesthetics

Some tzitzit manufacturers make their strings a bit whiter than others. Some have a few burrs and spurs, while others have better finishing. Some hang down straighter than others. And some have better reinforcement on the tips. Established tzitzit string makers of high repute include Mishkan Hatchelet, Srulovitz, K'Nesher, Netzach and Zeibert.