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^-1·cm^-2·µm^-1). This is equivalent to 10¹⁰ watts per steradian per cubic meter (W·sr^-1·m^-3). In practice, spectral radiance is typically measured in microflicks (10^-6 flicks). One microflick is equivalent to 10 kilowatts per steradian per cubic meter (kW·sr^-1·m^-3).