Surveyors use a variety of tools to measure distances and angles in the field. These include ranging rods, chains, tapes, theodolites, compasses, levels, and other instruments. Chains are available in different lengths and units - the Gunter's chain is 66 feet long divided into 100 links of 0.66 feet each, while the engineer's chain is 100 feet divided into 100 links of 1 foot each. Metric chains are made of steel wire with markings every meter and 5 meters.