Made of Stainless Steel spring and EVA padding, easy and comfortable to wear. _x000D_ When wear it on, it holds finger straight, then bend your finger against spring tension to rehabilitate finger. _x000D_ Use For: _x000D_ Disorder in stretching or bending finger caused by injury or arthritis against resistance. _x000D_ Interphalangeal joint extension applies to a variety of causes dysfunction. _x000D_ After long-term finger injury or arthritis caused by lack of straight or curved, the middle finger joint spasm reduction. _x000D_ This device can be an early self-rehabilitation exercises or at any time and place. _x000D_ Easy to use, effective rehabilitation activities knuckle, very effective _x000D_ How to choose the size: _x000D_ S:The circumference of the second finger knuckle is less than 5.5cm _x000D_ M:The circumference of the second finger knuckle is about 5.5-7.0cm _x000D_ L:The circumference of the second finger knuckle is more than 7.0cm _x000D_ Include:1pc