Black U-Lace Slims No-Tie Laces. Modular laces that are uniquely true-woven for an authentic look and feel. Usage: U-Lace Slims was designed specifically for Teen and Adult Fashion Sneakers that have a slimmer, more narrow/fashion profile. As seen on Shark Tank. 60% Polyester, 40% Lycra. Do Not Wash. OSFM (Teen & Adults).