Starrett 443Z-6RL Vernier Depth Gauge with Half Base, Micrometer Type, 0-6" Range, 0.001" Graduation, +/-0.0001" Accuracy Measurement range of 0 up to 9", and resolution of 0.001" Vernier scale for precise measurements in fine units Includes adjustable, 5/32" diameter measuring rods to cover the range, one rod per inch of measurement Two-inch long half base enables measurements close to shoulders and between obstructions Bases and measuring surfaces are hardened, ground, and lapped for durability and accuracy