[Photo: courtesy Allbirds] ALLBIRDS Allbirds entered the sweats game late last year, bringing colorful, sporty men's and women's separates made from a blend of organic Pima cotton, hemp, and an FSC-certified tree fiber called TENCEL Lyocell. The brand even prints each item's carbon footprint on the product. For example, a women's R&R sweatpant clocks in at 19.4 kg of CO2 emissions—roughly the same as what is emitted by a gallon of gas in a vehicle, according to Carbonfund.org —but the brand says the item is ultimately carbon neutral, thanks to a balance of credits in sustainability efforts and practices.