A review of the Allbirds Tree Flyer 2 - one of the best carbon-neutral running shoes on the market, but how does it compare to other everyday running shoes?
Product releases this week: Hoka, Stanley, Billie and more cnn.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from cnn.com Daily Mail and Mail on Sunday newspapers.