2-in-1 5mw 532nm USB Green Laser Pointer Pen /Ball Pen, $28

Specifications:

    * Power saving, durable and reliable
    * Unique toy that puts on a laser show anywhere and anytime you want
    * Woking Voltage: 3.0V
    * Wave Length: 532nm 
    * Output Power: 5mW
    * Material: Aluminum alloy  
    * Output Mode: Constant wave
    * Storage Temperature: -10~50°C
    * Powered by: Charging by USB/AC Adaper
    * Optimum Operation Temperature: 10~30°C
    * Size: 145 x 14mm / 5.7 x 0.6in(L x Dia.)

http://www.laserpointerworld.com/green-laser-pointer-pen-5mw-532nm-usb/