Baseball Bullet designed to develop, improve and maintain baseball athletic skills and technique. There are three device weights (light, heavy, extra heavy) and four length (short, medium, long, extra long). Go to Sizes Chart to see all device sizes and lengths. Do not enforce preparation by starting to practice with a heavy or extra heavy device size. The better way is to start with a light device size, improve an athletic skills, technique and go to a bigger one. Do not practice less than 30 feet from objects. A hand strap must be worn all time when practicing, to prevent mistakenly release a device from hands. Always check a device integrity before practice to prevent injury. Baseball Strike Extender is very effective to practice the right position before hit a ball, a device pass and direction. Easy to assemble and carry.