The main point of this toy is to count the number of times a pen/pencil is twirled. The toy is in the shape of a cylinder and allows for a pen or pencil to slide right through it, sort of like a sleeve. On the outside of the toy is a digital counter that keeps track of the number of times the toy is put into circular motion. The player has to twirl the pen around their thumb, which allows the counter to detect circular motion, which then increases the number of the counter. The goal of this is to set a high score in the number of times a pen can be twirled.
The physical principle of this toy is circular motion - a counter keeps track of the number of times a pen is twirled in a circular motion
The cost to produce this toy may be a bit more expensive than a simple plastic toy, simply because of the digital counter that goes along with the toy. This toy is very durable, it should definitely last for a few years, but the only worry is that the battery of the counter will run out. In that case, a replacement may be needed after long usage of the toy. This toy should not be in the hands of small children because its small width can potentially be dangerous (its diamater is not much larger than that of a pencil).