Founders Jonathan Schwartz and Keith Peterson have a pretty serious pedigree when it comes to the athletic-wear space: Schwartz is an Ironman finisher several times over (his father was also a co-founder of Calvin Klein Inc.), and Peterson spent the majority of his career at major fashion brands. The brand—named for the make-or-break split seconds on an athlete’s stopwatch—is a fast favorite for women who want their workout clothes to be as pretty as they are high-performance.