Measuring Head: The Ophthalmic Lens Clock is made of a special material with high smoothness to prevent scratching the lens and avoid wear and tear due to improper use.Shockproof Design: The Curve Optician Lens is designed to avoid falls and vibrations, ensuring accurate measurements every time.Durable Stainless Steel Shell: Crafted with a stainless steel shell, this tool is not easily damaged, promising long durability.Accurate Lens Measurement: By placing the measuring head vertically on the mirror surface, it provides precise data for lens measurement.Precise Scale and Pointer: The Curvature Measure Gauge features an accurate scale and anti shaking pointer that are clearly visible for easy reading. It's suitable for measuring lens curvatures of 1.53/1.599/1.61/1.67 values. Size Chart: 5.6cm/2.20inch Package Includes: 1Optometry Tool Note: Please allow slightly errors due to manual measurement and different monitors.