In optical engineering and telecommunications engineering, the flick is a unit of spectral radiance. One flick corresponds to a spectral radiance of 1 watt per steradian per square centimeter of surface per micrometer of span in wavelength (W·sr ·cm ·μm). This is equivalent to 10 watts per steradian per cubic meter (W·sr ·m). In practice, spectral radiance is typically measured in microflicks (10 flicks). One microflick is equivalent to 10 kilowatts per steradian per cubic meter (kW·sr ·m).