With twice the number of control pins of a standard mechanical timer, the SunBlaster 24 Hour Analog Timer provides unrivaled 15 minute precision. The non-removable pin design keeps pins safe and secure. The grounded outlet allows a wider variety of appliances to be used. It includes a helpful override switch so it can be powered off even if it's set to be on. This control is very useful with the SunBlaster Growlight Garden, and any other indoor lighting system. Generally speaking, most indoor plants, including seedlings, benefit from twelve to fourteen hours of light at a time. Twenty four straight hours of light will not harm plants, but it will interfere with later stages of the plants' maturity, as in fruit formation.