This was originally designed for students whom only have the use of one hand. This enables people with this disability (person with a limb difference) to remain independent when using a computer. The design works on all computers and laptops. This tool enables them use functions such as holding "shift" or “ctrl” while operating the mouse to select multiple items or do other key board functions. Then lift the tool off when they are done. For example some CAD software commands need this to be able to use the software. The weight is 3/8 bolt and nut with two washers and this can be adjusted to suit the keyboard you are using.