The sudre/kusti prayers are one of only two compulsory religious duties in Zoroastrianism. The other is observance of the gahambar (festivals). The sudre is made of cotton and is worn at all times next to the skin, like a vest. It is white to symbolize purity and has a small pocket at the front of the ‘V’ neckline in which the faithful are exhorted to store up good thoughts, words, and deeds. The kusti is a long lamb's wool cord, tied around the waist (unlike the brahman cord, both of which presumably originated in Indo-Iranian religion).
"Naujote." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (August 18, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/naujote
"Naujote." The Concise Oxford Dictionary of World Religions. . Retrieved August 18, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/naujote