1.Notice: If the working voltage is 100-240V, a transformer for 12V is needed, because the gu5.3 spotlights bulbs are low voltage 2.Easy installation: Standard MR16 shape dia1.971.85 inch with GU5.3 bulb base. Can be easily to replace traditional MR16 halogen bulbs and fit well into your fixture without problems. Perfect for landscape, recessed, lighting track, etc. Notice: this bulb is used to replace 1.97 inch MR16 halogen bulb, not 1.38inch diameter MR11 lamp. Warning : Please measure the dimension and bulb socket of your light fixture to confirm our bulbs can be used 3.Reduce cost and trouble of changing light bulbs: MR16 5W LED bulb with a lifespan over 30,000 hrs, can last very long time, save effort and maintenance costs on changing bulbs frequently. You could replace the MR16 20W 35W 40W traditional halogen bulb by only 5W LED 4.Healthy and comfortable LED bulb lighting: More vivid and natural LED light bulbs with high CRI >80. 450 Lumens. Not dimmable. No lead or mercury. No UV or IR radiation. transformer for 12V is needed, because the gu5.3 spotlights bulbs are low voltage