The ring light RL-21 with a diameter of 54cm can deliver light with a temperature of 2700 – 6500K. The color temperature refers to how warm or cool the color is. Light warmth is measured in Kelvin (K) and the lower the degree, the more yellow the shades, while the higher the degree, the more blue the shades. Low color temperatures of 2700-3000K provide warm lighting, intermediate temperatures of 4000-5000K provide daylight, and high color temperatures of 5000-6500K provide cool lighting.