Oura Ring 4 Sizing Kit Official Size Before You Buy New Sealed What it is: Oura Ring 4 Sizing Kit — plastic ring sizers for finding your correct Oura Ring 4 fit before purchasing. Available sizes 4-15 (no half sizes). Oura Ring 4 sizing differs slightly from standard US ring sizes, so this kit is the recommended way to size accurately. Purchasing typically earns credit toward a future Oura Ring 4 purchase through the retailer. Condition: New, factory sealed. We have multiple units in stock. Box may show signs of wear and scuffing but all boxes are still factory sealed. Shipping: Ships Mon & Thu, typically within 3 business days. May combine with other orders at seller's discretion; shipping not adjusted for combined orders. Questions? Message anytime.