W.F. McCollough Geotechnical Gauge
Make accurate and consistent observations every time! Features include centimeter and inches scale, roundness chart, chart for estimating percentage composition, 6 common Munsell® soil colors, Unified Soil Classification System (USCS), soil compaction tests for clay and sand, and size classification chart with actual sand grains from coarse to silt permanently fused to plastic card. Flexible, waterproof plastic card has nylon string for carrying convenience and measures 5” x 7”.