STRENGTHEN YOUR HANDS AND HELP REDUCE PAIN. The Flex-Grip is a super flexible polymer hand exerciser that helps improve your dexterity and flexibility. You can exercise finger muscles together or individually, helping to improve hand strength and easing pain and stiffness. Perfect for rehab, sports training and stress relief. Can also be heated or cooled for hot/cold therapy. Fits either hand. Washable. Latex-free.