- Wide range of ID measurements by combining extension rods (pipes) and anvils with the micrometer head.
- Carbide-tipped measuring faces are available. (series 137)
- The 139 and 140 series use highly-durable/ large-diameter extension pipes.
- Series 137 supplid in fitted plastic case except 1550mm/60in come in wooden case.
- Series 139 supplied in fitted wooden case except 500mm/20in come in plastic case.
- Series 140 supplied in fitted wooden case.