The bottom is indoor and out, very good grip to tile floor I?m afraid of falling so these give me confidence with a sure grip. Hi and welcome to another Dads Den Review. I live in Utah. I was amazed at this product for the price. The bottom sole is hard and makes quite a bit of noise on hard surfaces, I. With a family of 5, the choices for a bike rack that will carry all of our bikes are very limited - in fact, this is the only one I was able to find. It?s perfect fit for my Bose earbuds and charging wire. They are not supportive enough for me, even though they have a rubber/fitted bottom. The slip puffs out the dress perfectly. These lasted 10 days before the right channel broke when the buds were pulled from my ears.