Microfiber yoga towels are the perfect mat companion for yoga class. Most practitioners lay a large waffle-weave towel down over their mat to soak up sweat, and provide an nice surface to prevent sliding as you practice. These non-slip yoga sweat towels are especially helpful for hot yoga classes, like Bikram.
Many people will have a smaller 16"x24" hand towel, ready to wipe their hands or brow.