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. 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-OP10 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.170 * 20mm / 6.69 * 0.79in Item Weight: Approx.75g / 2.63oz Package Size: Approx.19 * 11 * 4.2cm / 7.48 * 4.33 * 1.65in 1 * Direct Ophthalmoscope 1 * Storage Box