Optical retractable whip can be attached to the screen surface operation, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the length of the pen can be extended, the Pen ye tɔ̈u në kë ye cɔl hollow design, control light can be shot through a small hole in the middle of the pen, allowing users to do near-screen operation.