KENDALL + KYLIE Open Back One Piece in Blue. - size S (also in ) KENDALL + KYLIE Open Back One Piece in Blue. - size S (also in ) 50% nylon 34% poly 16% elastane. Hand wash cold. Adjustable shoulder straps. Stretch fit. KENR-WX78. KSSU180015BK. The Kendall + Kylie collection offers clean and crisp pieces that are both fashion-forward and modern. The line fuses Kendall's refined feminine style and Kylies dynamic edgy streetwear in a mostly monochromatic color palette with pale pink and blue accents. The latest Kendall + Kylie collection is a true reflection of the Jenner sister's lifestyle and fashion tastes.