This model is available in gauge lengths from 2 inches (50 mm) and larger, with measuring ranges up to 4 inches (100 mm). It is a uniquely designed unit that may be left on through specimen failure. These extensometers are widely used where long samples are required. They are ideal for testing steel re-bar, weld joints, and wire materials.

Designed by Epsilon Technology, Model 3543 was created to survive specimen failure by separating into two halves, thus preventing permanent damage to the module body. During operation, the upper half of the extensometer pulls out of the main body. Tapered measuring beams activate strain gauged flexures within the unit. This unique design allows long measuring ranges, yet retains the compatibility with electronics for strain gauged transducers. These models offer high accuracy and are light weight but rugged, with low operating force. They are tension only units.