◆ Coxial parallel light principle ◆ 6 different apertures with red-free filter & blue filter they can be switched ◆ 29 kinds of adjustable corrective lenses, Range of lenses：-35D-+40D ◆ 4000k color temperature LED bulb as light souce ◆ Li-ion rechargeable battery so long life ◆ Micro USB charger interface so convenient charging ◆ Deluxe metal handle, strong and durable