Features： 1、PROFESSIONAL: Red green color pure, can be complete filter, red and green color complementary, effectively avoid detection bias. 2、FUNCTION: For fusion, suppression and diplopia testing and training. 4 dot optometric flashlight with red and green glasses and battery charger. 3、ANTI SLIP FLASHLIGHT: The flashlight in this set of optometry tools has an anti slip design, which is easy to hold and not easy to slip off when using. 4、1200MAH BATTERY: Built in rechargeable battery. 1200mAH rechargeable lithium battery, small size but high power, service life of 2 to 3 years, can be cyclically charged 500 times. 5、DURABLE: Made from hard, durable plastic, the 4 dot test tools are lightweight and virtually unbreakable. Include the red green glasses, and instructions manual. Specification： Item Type: 4 Dot Red Green Light Glasses Material: ABS Built in Battery: Lithium ion battery 1200mAH Product Function: 1. Wearing red and green glasses to observe the four dot light, the use of color complementarity of this situation, the separation of the two eyes. 2. To determine whether there is visual fusion dysfunction in the two eyes in the case of separation of monocular inhibition at the same time. Package List： 1 x Four Dot Light 1 x Storage Box 1 x Instruction Manual 1 x Glasses 1 x Battery Charger