I'm selling this because it no longer fits. As the photos show, there's a thread break, but it doesn't affect wear. The lining is mesh, making it a cool T-shirt. Width: 43cm Length: 57cm (Similar to a Uniqlo or North Face S size) How about it for trail running or the summer mountain season? Fitness round neck short sleeve T-shirt, pink synthetic fiber material. - Color: Pink - Material: Synthetic fiber - Design: Round neck - Style: For fitness - Sleeves: Short sleeve Thank you for looking.