The Qura Ring 4 Sizing Kit by Oura is designed specifically for the Oura Gen 4 model. This sizing kit is intended for use on the hand and is tailored for individuals engaged in running and jogging activities. Made in China, this kit ensures a perfect fit for optimal performance during workouts. Perfect for athletes looking to enhance their training experience, this sizing kit is a must-have accessory for those using the Oura device.