Tzitzit consist of four specially prepared strings, which are inserted through a hole in each of the four corners of the garment so that they emerge from both of its sides, thereby doubling their number to eight. One of these strands is longer than the others, and it is called the shamash.

After the strings are threaded through the hole in the corner of the garment, they must be tied firmly with a double knot. The shamash is wrapped around the other seven threads several times, and then another knot is tied, and this is repeated another three times. There are various customs regarding the precise manner in which the shamash is wound around the other strings and in which the strings are tied together, and each person should follow the practice of his community.