The OttLite 13 watt replacement tube delivers the right mix of brightness and contrast to bring true colors and comfortable clarity to your world so you can enjoy your time even more. You’ll see colors accurately and fine print and details with ease under this unique low heat, low glare illumination that helps reduce eyestrain. Please note this version has a magnetic ballast and will work with OttLite 13W lamps purchased before 2008. Details:Replacement bulb type AFor use only as a replacement bulb with specific OttLite lamps with a magnetic ballastTrue colors, clear details and reduced eyestrainLow-heat, low-glare illuminationEnergy efficientRated to last up to 10,000 hours