Features: 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. 5 different apertures. 19 kinds of adjustable corrective lenses; range of lenses: -20D~+20D. 4000K color temperature LED bulb and XHL Xenon Halogen bulb for choosing. The clip with integrated on/ off switch for simple use. Powered by 2 AA batteries (not included), easy to install and replace batteries. Compact size and lightweight design for easy storage and convenient transport. Elaborate design and reliable quality. A classic instrument for physician. Note: Please read the user manual carefully before use. Specifications: Model: HS-OP10S/ HS-OP10 (Optional) Main Color: Black Main Material: ABS Illumination: Direct Illumination Luminance: 14 Lumen Bulb: 106 2.5V, 0.5A; 206 3.0V, 0.08A Power Supply: 2 * AA Battery (Not Included) Operation: Temperature 10~35, Humidity 30%-70%, Air Pressure 700hPa-1060hPa Storage & Transport: -20~70, Humidity 10%-90% (without condensation), Air Pressure 500hPa-1060hPa Item Size: Approx. 173 * 18mm / 6.81 * 0.71in (HS-OP10S) 170 * 20mm / 6.69 * 0.79in (HS-OP10) Item Weight: Approx. 63g / 2.21oz (HS-OP10S) 75g / 2.63oz (HS-OP10) Package Size: Approx. 19.2 * 10 * 3.7cm / 7.56 * 3.94 * 1.46in (HS-OP10S) 19 * 11 * 4.2cm / 7.48 * 4.33 * 1.65in (HS-OP10) Package Weight: Approx. 187g / 6.59oz (HS-OP10S) 294g / 10.38oz (HS-OP10) Package List: 1 * Direct Ophthalmoscope