Meet HeatGear® Sonic: UA's newest and greatest baselayer innovation. Under Armour started the "performance" revolution with their original HeatGear® compression-the ultra-tight fit that increases muscle power and makes you feel invincible. This latest UA fabric wears like a second skin so you get the same powerful compression, plus extreme comfort for all-day wear.
That does exactly what it says on the tin. I do boot camp every Saturday (as an Instructor) and I can certainly recommend this product. The compression is spot on and they will also keep your muscles warm throughout your chosen physical workout. Buy these as you will not be disappointed. Buy a size one larger than you normally would as the waist band is a snug fit!