Material: the pens are made of premium aluminum alloy body and high quality LED bulb, Design: Top with push button on/off switches, easy to control, Convenient: metal pocket clip, lightweight and portable, fits easily in your pocket, Compact and portable: this penlight is 5 ,3 inches long, powered by 2 AAA batteries (not included), Professional and efficient: The penlight with pupil gauge and ruler board on both sides of the pen light is very useful for measuring height of the pupil and the patient's body, Specification: Material: aluminum alloy Color: Black Light Color: White Power By: 2 AAA batteries Size: 13.5cm (5.3inch) in length x 1.3cm (0.21inch) in diameter Package includes: 5pcs Penlights