KY-008 650nm Laser sensor Module 6mm 5V AB021
You can use this laser transmitter for theft detection, or to use it as a pointer. It is operated from a 5V source, which makes it good choice to connect it to Arduino. It has a wavelength of 650nm and power dissipation of 5mW. However, do not try to bring the laser to the eyes since it might lead a serious injury.