The arrival was very timely, and I was in good health, but the balance was really bad, so I purchased this balance board to practice my sense of balance. I found it to really improve my balance board. Start my one foot and keep it balanced. My core is powerful, but some things have disappeared. After just 5-10 minutes, in order to maintain balance, he clicked almost every week and I balanced for about 20 minutes. This is a sandpaper-like surface. I never barefoot, but barefoot doesn't feel uncomfortable. I don't even feel rough. High quality products at reasonable prices.