Tennis racquets come in varying sizes, particularly in terms of a head dimension, weight, length and a grip size. Many players have a tendency to select a smaller grip because it gives them more secure feeling. Professional tennis players keep a racquet close to a grip butt for increase a racquet mobility, it makes swing faster and adds additional spin and speed to a tennis ball. For beginners and intermediate players, a smaller grip size more difficult to control and usually they squeeze a tennis racquet handle tight. A tight grip restrains wrist mobility, reduces a swing and makes a tennis ball speed less. A length of a grip is individual and ranges from 7 to 10 inches (17.8 to 25.4 cm). Two handed technique tennis players use a longer grip than a one handed. Usually, tennis players choose a grip size they can hold comfortable. Every racquet has a sweet spot – this is the area of the string bed that produces the best combination of feel and power. Tennis Bullet devices are different by length and weight. The longest recommended size is 21 inches (53.3 cm). This is an overage length from a grip butt to a sweet spot. The recommended grip length is from 7 to 10 inches (17.8 to25.4 cm). The length of a grip can be customized by a player. The smallest comfortable size of a device is better for feeling, practice swing, to learn how to keep a racquet grip with fewer fingers and close to a grip butt. Hand Strap designed to prevent not intentional device release from a hand in time of practice and brings confidence to learn a swing and wrist action.