Lost profits, according to the “entire market value rule,” may be recovered based on the value of the entire device including non-patented materials or components provided that a functional relationship exists between the patented device and the unpatented material or component. A functional relationship between a patented device and an unpatented material used with the device is not precluded by the fact that the device can be used with other materials, or that the unpatented material can be used with other devices.