0 but Im glad I have one lying around. they?ll work for my husband . The wheel rolls smooth and effortlessly (pending the weight you?re using). The company has not responded to my inquiries. Comfortable like the ugly Crocs. They are a tad big in the toe, but the heel secures nicely and I am not slipping out of them. So happy I discovered this product. He did his maintenance work without back ache. The sound quality is great and the background noise reduction is top notch, I have a bit of a large head and initially felt tight but after adjustment its fine. If you dont want to hear that, just put in soft earplugs and they still work perfectly!