I wore this about 2 or 3 times for about an hour of walking. It's light and packs down small, making it convenient as a spare T-shirt for travel. Product Overview: Product Information This extremely thin T-shirt is made by knitting the fabric extremely thinly, making it less likely to trap heat and providing a very cool feel. It uses the lightest knit material in Montbell's T-shirt category, minimizing stress during exercise. High breathability and moisture-wicking properties keep you dry and cool at all times. It is also treated with antibacterial processing, providing excellent deodorizing effects. It is ideal for high-intensity activities such as hiking in the low mountains in midsummer and trail running.