Silicone and TPR Ball Stretchers
Beginner ball stretchers tend to be made out of soft, pliable materials like silicone and TPR. Although they can cut off blood circulation, their effects are typically pretty mild and they are considered a safe entry-level toy for people looking to try ball stretching. The stretch they provide comes from their height - taller rings stretch the skin more than shorter ones. These stretchers typically required lube to apply.
Example of a TPR/silicone blend ball stretcher. Shown: Perfect Fit Bull Bag.
Leather Ball Stretchers
Next up are leather ball stretchers. Like other soft stretchers, they typically don't permanently elongate the scrotum, but they can provide some intense sensations. However, people also pair these with an attachable metal weight to make results more intense and/or more permanent.
As a person becomes more comfortable with this type of play and decides to opt for something more intense, metal ball-stretchers are the next option. These rings are inflexible and also considerably heavier, which makes for a more intense stretch and sensation. Some can be stacked together for added vertical stretch as well as weight.
There are lots of other varieties of metal ball stretchers. Some include screws to tighten them and provide more intensity. Long-term use of heavy metal ball stretchers can permanently elongate the scrotum.
Buying and Using a Ball Stretcher
For those looking to buy a ball stretcher, it is important to measure the circumference of the area just above the balls to ensure it will fit. Many manufacturers give precise instructions for measuring for a ball stretcher. You should follow these carefully as many sex toys cannot be returned once they have been used/opened.
Ball stretching can cause permanent damage, so it's important to increase the amount of time spent using the device gradually and to pay attention to sharp pain and remove the device immediately if it occurs.
If permanent stretching is the goal, it is important to stretch regularly and gradually over time.