This is a great product that increases his grip strength. This object is distinguished from others by its original design: you can choose to work the whole hand or just a finger ... for example for rehabilitation. I bought it for my son so that he improves his grip kimono (Kumikata for specialists) ... I chose this model (5kg) suitable for people who already have a certain strength. His aesthetic side you will take him wherever you go and train at any time. Finally, its quality and strength really appear excellent!