This 2-piece professional pen light is specifically designed for nurses, doctors, and EMTs who need a reliable, compact examination tool. Each pen light features a bright white LED that provides focused, shadow-free illumination ideal for pupil response tests, throat checks, and wound assessment. A built-in pupil gauge and centimeter ruler are printed along the barrel, allowing quick neurological evaluations and precise measurement of lesions or injuries. The ultra-portable, lightweight design easily fits into a pocket or medical kit. Please note: batteries are not included, so you can use your preferred AAA batteries for dependable performance.