Features: The moving parts made of special wear mainly stainless steel,with good resistance and anti-rust properties. Simple structure,convenient and stable operation. Shockproof structure of rack. Hardened alloy measuring head. Specifications: 3 extensions inside, the depth can be extended to 100mm. Digital depth indicator(0-25m, 0-100mm are 6 keys): Measuring range: 0-12.7mm. Division value: 0.01mm. Precision: ±0.02mm, ±0.03mm, ±0.04mm. Measuring range: 0-25.4mm. Measuring range: 0-50.8mm. Digital depth dial indicator: Measuring range: 0-12.7mm, 0-25.4mm, 0-50.8mm. Precision:±0.003mm, ±0.005mm, ±0.006mm. Package Includes: 1 x Digital Depth Indicator (battery 3Vx2 Not included). 3 x Extension Rod. 1 x Allen Wrench. 1 x User Manual. Notes: 1. Electronic indicator depth gauge is a precision measuring tool, therefore when using, prevent from shock, drop, to avoid loss of precision. 2. Keep it clean, and avoid the penetration of liquid, such as water, which will influence the normal use. 3. Do not apply voltage on any part of the gauge, do not engrave letters so as to avoid damage on the electronic circuit. 4. If don't use for long time, remove the battery.