Reasonable design: with reasonable design, it has firm clasp, and not easy to loosen. Soft and durable: it is made of semi soft material, flexible twist and not easy to break, it is wear-resistant and durable, has long service life. Anti slip: it is anti slip with bottom groove design, which is practical and safety. Sensory training equipment: it can improve children's attention concentration, motor coordination ability, and coordinate the relationship among psychology, brain and body. Easy to install: first, jam the short side of the clip, then close, which exercise children's hands and brains. This children's physical fitness training device can improve children's attention concentration, motor coordination ability, and coordinate the relationship among psychology, brain and body. Specification: Material: plastic Suitable for: over 3 years old Applicable age: children (4+ years old) Color: red/yellow/blue/green/pink (two for each) Size Chart: M 28cm: diameter: 28cm, inner diameter: 24cm L 38cm: diameter: 38cm, inner diameter: 33cm Package Includes: 10 Pieces circles (red/yellow/blue/green/pink (two for each)) 10 Pieces clips 1 sand bag(random color) Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!