Features 1、EASY TO CARRY: This strabismus measurement tool with a double stand is portable and easy to use, and is an important reference in assessing binocular vision and managing binocular vision abnormalities. 2、ACCURATE TESTING: This strabismus measurement tool can accurately measure AC/A and is suitable for near and far measurements. 3、ESSENTIAL TOOL: This strabismus measurement tool is an important and essential tool for binocular vision examinations. 4、MAIN APPLICATION: This strabismus measurement tool can be used for horizontal and vertical occult strabismus; rotational occult strabismus; and examination of unequal images. 5、ABS MATERIAL: This strabismus measuring tool is made of ABS plastic, which has good wear resistance and is lightweight. Specification Item Type: Eyeglasses Optometric Testing Tool Material: ABS Use: Quick check eye position AC / A Product Power Supply: 2 x AAA dry batteries (built in carry) Single capacity 600mAh Package List 1 x Eyeglasses Optometric Testing Tool 1 x Holder(Random color) 1 x Trial Frame 4 x Hole Mirror 2 x Test Sheet 1 x Instruction