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Ten Thousand Interval Short ($68)

Ten Thousand is a brand that produces training clothes that can be custom-fit, beyond just a classic sizing guide. With the Interval Short, you can choose between a five-, seven-, and nine-inch inseam, 16 different colorways and patterns, and whether or not you want a liner. "Our brands are aligned, and they do a lot of community efforts," McCarthy says of the company. "It's been great to see the brand grow and we love collaborating with them whenever possible."