Simulate a gradual sunrise and sunset every day! the single ramp timer is a fully programmable 24 hour LED lighting controller that not only turns your lights on and off, but also simulates a gentle sunrise and sunset for your critters. Designed for both freshwater and marine aquariums, it's extremely simple to use and slowly acclimates animals to the bright light that LEDS produce. This Slow acclimation helps reduce stress often caused by sudden light intensity changes and provides a more natural rhythmic daily light cycle. At the pre-programmed on time, the single ramp timer slowly begins to mimic a morning sunrise and gently increases the lighting level to full Brightness over 15 minutes. When the programmed off time is reached, it gradually dims the light over 15 minutes before turning off, simulating a soft dusk to night effect.