This Extra Firm Black Gel Ball is from our range of Hand Exercise Balls and is the firmest ball in the range, offering the firmest level of resistance available.Hand Exercise Balls are very easy to use therapeutic aids that offer variable levels of resistance training exercises for hand strengthening exercises, weakened or injured hands, fingers and forearms. The gel ball is pleasant to touch and returns back to its original shape after each squeeze. Hand Exercise Balls are supplied in a wide range of resistance levels, all of which are available in this area of our shop. Perfect for use at home, the office or in the clinic, the gel ball is small enough to keep in a handbag or pocket for easy transportation.