Here's what other sites are saying:
The Icebreaker Chakra Long Sleeve Half-Zip top from Icebreaker has great range, taking you from mountain biking to hiking to spring skiing. Made of soft, nonirritating merino wool, this long underwear top resists odors naturally. Merino wool wicks away moisture and breathes to regulate temperature for outstanding comfort in a variety of conditions. With a UPF rating of 50+, fabric offers very good protection from UV light. Raglan sleeves eliminate shoulder seams for increased range of motion and comfort. Versatile zip T-neck styling lets you zip up for maximum heat retention and unzip for ventilation. Machine washable, line dry or dry flat in shade.