Strain gages consist of a very fine and thin metallic foil etched in a grid pattern, which is bonded to a device and used to measure the strain, or amount of deformation of the device when load or pressure is applied. The resulting electrical output is proportional to the strain. Because these strain gages are so small that they are negligible in mass, they excel in sensitivity, stability and fatigue with no inertial effect. They are also an easy-to-handle device, whose operating temperature range is wide. The strain gages can be used to measure the strain of all kinds of materials, regardless of metal or plastic.