UV lamps vary both in size and power. Smaller lamps usually have one bulb and it can be quite difficult to place the entire hand in UV light. These lamps need the nail sides to be properly cured if they are to be effective. Some UV lamps with just one bulb include mirrors to reflect the light around the nails and help the gel to cure evenly. Larger UV lamps (often with 4 bulbs and a timer) are the most convenient to work with as they allow all the nails to be evenly cured at once, and in the shortest time. These usually feature 9w bulbs, though some weaker bulbs also work well but just require more curing time for the gel. If the gel starts to take longer to cure than previously, and / or the resulting shine is not so strong anymore, it is probably time to change the bulbs. NB! There is no need to worry if Mereneid Sari gels are left under UV light for longer than recommended, as unlike with some other gels, it will not affect their quality finish.