STARRETT Depth Gage Micrometer Set - Model: 449BZ-3R Type of Reading: Inch Measuring Range: 0 ~ 3" Base Length: 4" ROD DIAMETER: 1/8" NUMBER OF EXT RODS: 3 Go to amazon.com Related posts Which is the best depth micrometer set? FeatureFitted case includedSatin chrome finish - no glare.The bases are hardened, ground and lapped for long lasting precision. DescriptionExcellent for measuring the depth of most holes, slots, shoulders and projections.