Feature: 1. 2 models for option: HS-OP10S/ HS-OP10. The differences between them: HS-OP10S has simple handle. HS-OP10 has standard handle that is more handy and convenient; and adopts coaxial parallel light principle. 2. 5 different apertures. 19 kinds of adjustable corrective lenses; range of lenses: -20D~+20D. 3. 4000K color temperature LED bulb and XHL Xenon Halogen bulb for choosing. 4. The clip with integrated on/ off switch for simple use. 5. Powered by 2 AA batteries (not included), easy to install and replace batteries. 6. Compact size and lightweight design for easy storage and convenient transport. 7. Elaborate design and reliable quality. A classic instrument for physician. Specification: Ophthalmoscope is a classic device for ophthalmology. This device adopts a professional lens system, which makes doctors conveniently get a clear visual field for examining the interior structure of eyes, such as dioptricmedia etc. Specifications: Model: HS-OP10S Main Color: Black Main Material: ABS Illumination: Direct Illumination Luminance: 14 lm Bulb: 106 2.5V, 0.5A; 206 3.0V, 0.08A Power Supply: 2 * AA Battery (Not Included)Operate: Temperature 10℃~35℃, Humidity 30%-75%, Air Pressure 700hPa-1060hPa Storage and Transport: -20℃~70℃, Humidity 10%-90% (without condensation), Air Pressure 500hPa-1060hPa Item Size: Approx. 173 * 18mm / 6.81 * 0.71in Item Weight: Approx.63g / 2.21oz Package Size: Approx.19.2 * 10 * 3.7cm / 7.56 * 3.94 * 1.46in . Package List: 1 * Direct Ophthalmoscope