Manufacturer: NaturalPoint. These flexible rubber Rings fit easily on your finger, and have a reflective crown. The SmartNAV Ring lets you control your computers cursor without taking your hands off the keyboard. When you slip on the Ring, the Smart-NAV follows your finger, allowing you to perform all typical mouse functions by simply aiming your finger at any point on your monitor screen and clicking with your user defined Hot Keys. One size fits all, adjustable. The package includes 2 Rings.