This core balance disc is a great introduction to balance training. To help prevent you from slipping and to vary your workout difficulty, the balance disc has a different texture on each side. One side is smooth and the other is tactile. It's the perfect equipment to get you familiar with balance training. The balance disc can be deflated to 1" thickness or inflated to 2" thickness for maximum comfort and to vary the difficulty level of your workout. Use the equipment for balance and stability exercises while standing or sitting. The 17.5" disc is roomy enough to stand on with both feet. Inflate to your desired level with a foot pump; available in blue only.