The compact sized 66fit Adjustable Hand Grip Exerciser allows you to adjust tension from 5kg to 20kg or 10 to 40kg.FeaturesMaterial: PlasticColour: White/Orange (5kg - 20kg)Colour: Black/Silver (10kg - 40kg)DescriptionBy simply twisting the white knob you can increase or decrease the tension of exercise. It is an excellent way to build up hand and forearm strength and is ideal for anyone in early stages of rehabilitation right up to people who want to increase general strength because you can adjust the strength to your requirement.Suitable for anyone who needs to increase their hand strength, with the added bonus of being able to increase the tension as your strength improves.