Hand held weight units of light weight manufactured as a solid unit, a shell unit with core insert combinations or modular units with interlocking ends. Shell units with core inserts and modular interlocking units allow for the changing of held weight by inserting or removing inserts or by locking or unlocking of modular weight unit sets creating varying held weight. The weight units are primarily used with upper body exercises during aerobic exercises in the home, outdoors, or in a gym setting such as walking or running to vary the intensity of workout during use.