Main Unit for Tubular Inside Micrometer 339-102This is an extension pipe type inside micrometer that offers you the following benefits: Interchangeable extensions in a hollow pipe design. Carbide measuring faces. Digimatic type with data output. It has excellent resistance against water and dust (IP65 protection level) enabling you to use it in machining situations that include splashing coolant fluid. Specification Digital Analog: Digital Inch Metric: Inch Metric Range: 8 9 " Measuring span: 25