From website: Whether you're cranking 4x4s in the bouldering gym or putting in serious burns on your project, the Black Diamond Notion Pants provide a comfortable, breathable fit. The soft elastic waistband layers comfortably under a harness, and reinforced knees stand up to chimneying, kneebars and other full-body tactics.----Stretch cotton twill (190 gsm, 97% cotton, 3% spandex)