NSF Indira Rib Waist Crew in Black. - size S (also in XS) NSF Indira Rib Waist Crew in Black. - size S (also in XS) Cotton blend. Ribbed waist panel. Ruffle trim. Terry fabric. Made in USA. NSF-WK51. 20004 IWFT. Based out of California, NSF has caught the eye of many. With their clean design and boyish charm, NSF is recognized for its relaxed, modern style looks.