Please note that this product is only compatible with 120V and cannot be used with a 12V RV system. Before returning the item, please verify that it will work with your fixture. This is a pack of four F15T8 LED Tube Lights that are 18" in length (17-3/4" actual length). They consume 7W of power but provide the same brightness as a 15W bulb. These lights emit a daylight white light at 5500K and have a frosted cover. They are double-end powered and can be used with a voltage ranging from 85-265VAC. They are ideal for replacing fluorescent bulbs in under cabinet lighting fixtures. The end caps of these lights are rotatable, allowing you to adjust the light forwarding angle by +-90 degrees to fit any fixture. These lights are easy to install and provide a bright light. The process of converting old light fixtures to use these LED bulbs involves removing the ballast and rewiring, which is simple to do. Before inserting the LED tubes, it is necessary to bypass the ballast and rewire your fixture. Connect the positive wire to one end and the negative wire to the other end. If you experience any defects with the product within 2 years, please contact us for a resolution. Please note that these LED tubes are instant-on and have a daylight white light at 5500K, making them suitable replacements for standard 18" CFLs that operate on 110/120V. The actual length of the tubes is 17-3/4" from pin to pin. It is important to note that these tubes are only compatible with 120V systems. Before making a purchase, please check your voltage to ensure compatibility and avoid the need for a return.