What are the betabrand petite pants made of? betabrand petite pants are made of 94% cotton and 4% elastane. They're pre-washed and have a silver lock-stich at the waistband. Why are betabrand petite pants so popular? There are a few reasons. inspired by popular appeal (i.e. It's clear that the trend is definitely here to stay, and we're sure that you'll love every second of it. There's nothing quite like a healthy workout in a comfortable pair of tights, right? And if they're cute too, that just gravyishes the divine. As the movement grew and more people came to identify with it, they began to dress in more hippie-style clothing. Whether you're looking for a light but comfortable pair of pants or a pair that boast some of the newest tech properties, we've got you covered. Be sure to check out our selection today and see which activewear pant is just right for you.