SPANX Supersmooth Undie-tectable Brief in Black. - size 1X (also in XS, S, M, L, XL) SPANX Supersmooth Undie-tectable Brief in Black. - size 1X (also in XS, S, M, L, XL) 77% nylon 23% elastane. Machine wash. Pull-on styling with elastic waistband. Item not sold as set. SPAN-WI275. SP0215. SPANX Inc. is a dynamic women's brand that has revolutionized an industry and changed the way women around the world get dressed. When SPANX founder and CEO, Sara Blakely, invented footless pantyhose, she got her foot in the door, but the inspiration to continue inventing was driven by her passion to make things better and more comfortable for women. Today, SPANX is a powerhouse lifestyle brand, offering both innerwear solutions and figure-flattering outerwear, constantly identifying and solving problems from a woman's point of view. With smarter, more comfortable, must-haves including shapewear, bras, undies, leggings, activewear, Arm Tights, and denim, SPANX elevates women through product and empowers them to look and feel their best.