Sustainable footwear and apparel company, Allbirds, has released a new version of its Dasher running shoe, which it claims has improved performance while lowering carbon emissions.

The Dasher 2 produces 10.7kg CO2e per pair, vs 11.3kg CO2e for the original Dasher. According to Allbirds, the lighter midsole and elimination of the wool eyelet are to blame for the weight loss.

The Dasher 2 has the potential to be carbon negative, according to Allbirds, because of its natural materials and responsible sourcing techniques. The San Francisco-based company claims to be carbon-neutral because it offsets the carbon footprint of all of its products to zero.

The Dasher 2 is powered by renewable natural materials including moisture-wicking eucalyptus tree fiber (Tencel), sugarcane (SweetFoam), and natural rubber (Forest Stewardship Council certified) (Forest Stewardship Council certified). Allbirds says the plusher cushioned SweetFoam mid-sole helps transition and reduces the shoe’s weight.

The shoe has been put through its paces by nearly 100 runners over a distance of more than 1,200 miles. It features a redesigned lug pattern for increased traction and additional reflectivity for dawn and night runs.