It comes in a variety of sizes ranging from 10mm to 80mm in diameter. Due to its inherent nature, the cable, especially in smaller diameters, is easily damaged. The radius that the cable can be bent to is usually restricted to a minimum of 1.5m. It usually comprises shorter sections connected by joints that can be up to 250mm diameter and 1.5m length. Depending upon the system installed it may have signal amplifiers (repeaters) between 20 and 180km in between sections. They can be up to 350mm in diameter and 3m in length and usually have to be cooled to below 30°C.