I use Underarmor cold gear and heat gear. They work great for me here in New England. I've heard that cheap brands colors run and stain your armor. We once had a Trooper throw his top in the bin on his armor after a troop. And a week later when he opened it he found his chest plate stained black! With polish and a lot of elbow grease it came clean. Lesson learned, cheap is not always the same and don't store undersuit in bin on armor.