Glass Fiber Reinforced Plastic (GFRP) in a wire form is used to protect the fiber in this product. This makes it suitable for use in the harshest of environments when for example, embedded in other materials. Position and number of sensors are defined by customer. A Draw Tower Grating (DTG®) array is embedded in a Glass Fiber Reinforced Plastic (GFRP) round profile. The DTG® array embedded in the GFRP is designed to measure the total strain caused by both the thermal expansion and the mechanical stress. The position and the wavelength of each DTG®, as well as the pigtail length and connector type, are specified by the customer. The sensor is intended for readings made with a high resolution FBG interrogator.