Specifications: 1. It's one-sided. 2. It's horizontal.There is also vertical style.Please see link:http://www.jhoptical.com/LY-23NS.html 3.Test distance is 30cm .Led illuminated near vision acuity. It's for weak sight,hyperopia and presbyopia testing. 4. Packing: 29cm x 20cm x 6cm, gross weight:0.5kg
Features: 1.Using high-tech light-emitting,power saving,slim and accuracy testing. 2.High brightness and uniform light-emitting make every chart be with consistent brightness contrast.It ensures accuracy testing. 3.LED photoelectric conversion efficiency is more than 80%.the same brightness of the light just around 10% of the electricity needed to traditional fluorescent lamp. 4.Protect eyesight: DC drive, no flash(Normal lights are AC drive, it will inevitably produce strobe). 5.Health: Healthy light contain ultraviolet and infrared light, no radiation (ordinary light contains ultraviolet and infrared). 6.Green: no mercury,xenon or other harmful elements, and will not produce electromagnetic interference (ordinary lamp contains mercury and lead elements, electronic ballasts will produce electromagnetic interference). 7.Long life: life of up to 100,000 hours. 8.Safety factor: safety voltage, current, and smaller, less heat, no security risk.