Inside precision micrometer series 561, range 100-350 mm, measuring head 100-125 mm, extensions: 25, 200 mm, delivery in wooden case, neutral, carbide measuring faces for micrometer head and extension rods , points of extension rods are spring loaded, optional accessory: gage block accessory (code 6881), cylinder gage block (code 4001), caliper/height gage checker (code 6884)