Order quantity is in feet. The three strands are jacketed together in a clear PVC outer jacked and the total diameter of the cable is 3mm. The larger the overall strand sizes the larger area of light output you will achieve. This product can be used for fiber optic lights, fiber optic curtains, fiber optic chandeliers and a wide variety of other applications. The nicked fiber optic cable gives a very distinct lighting effect and we suggest that you use a 150 watt metal halide illuminator to light the sparkle cable. This product is suitable for indoor, underwater and outdoor use as well. It can be used in waterfall features as well. We will also be selling crystals to attach to the fiber optic sparkle cable as well.