A sex toy used to extend the length of a person's scrotum.
The purpose is to stretch the scrotum, through a device or apparatus.
It is also a means used in CBT, to provide both pain and pleasure to the person wearing it.
For stretching, the goal is to wear this 'sex toy' for prolonged periods of time, to cause the scrotum to become elongated.
This generally takes several months, and cannot always be noticed, due to the natural elasticity of the scrotum itself.
The two basic types are one of leather, rolled into a tube, that is attached by clamps or such, that pushes the skin downwards.
Another is two halves of metal, attached by screws, that accomplishes the same thing.
These items can be locked into place, to further add some weight, which creates the drag, that helps shape the leather like skin of the scrotum.
Some can have added weights attached, to as much as 5 pounds, and some can have hooks attached, to raise the weight to ten pounds or more. (see Parachute (BDSM) )
Noteworthy: A ball lock can be used, to add weight, for when using over a prolonged time frame.
This can be further 'locked' by a padlock, which not only adds weight to the scrotum, but as a means to prevent a submissive from being able to remove the ball stretcher.