WTFrs Premium Warm Ups/Sweat Pants are printed on Premium Bella+Canvas Sponge Fleece. Yes, we could have gone cheaper, but we could have also bought cheaper bikes.
They are super comfortable, very soft and stretchy, warm, and feel like silk on the inside.
For reference, a 34" waist fits awesome in a Large and a little loose in a XL. 
Material:
8 oz., 52% Airlume combed and ringspun cotton, 48% polyester fleece
Athletic Heather is 90% combed ringspun cotton, 10% polyester
 
Feature:
White cord drawstring, unisex sizing, retail fit
Tear away label
BELLA+CANVAS uses sustainable manufacturing processes with Blue Sign certified dyes, efficient dye houses that adhere to the state of California’s EPA regulations around waste water treatment and usage, and cutting facilities in Los Angeles that run on partial solar power with comprehensive recycling programs for paper waste and fabric scraps.