Features: The R13 small rings with Crystal Charging Case (Silver) combines health monitoring and gesture control, featuring real time body temperature trackings , sleep analysis, step counting, and smooth /APP data synchronization for comprehensive wellness management. Crafted from steel, this IP68 rate wearable operates in 0 45°C environment with ±6KV contact/±10KV air electrostatic defense , supporting 12+ sports type and remote cameras control via hand gestures. Ideal for fitness enthusiasts, professionals, and health awake users search cautious activity trackings during workouts, office hour , or travel. Perfect for gym meeting with sweat resistant durability, outdoor activity with temperature stable performances ( 10 55°C storage), and small home integration through motion controlled gaming/app interactions. Engineered with sleep optimization algorithms and 45°C charging safeguards, its ergonomic design ensures whole day comfort while syncing vital through encrypted connection . Specifications: Material: steel No.9: Inner diameter 19mm, perimeters 57mm No.10: Inner diameter 19.9mm, perimeters 62.5mm No.11: Inner diameter 20.7mm, perimeters : 65mm No.12: Inner diameter 21.5mm, perimeters 67.5mm Package Includes: 1 set small rings note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the differences between different monitors, the picture may not reflect the actual colorful of the item.