There is a light-activated titanium rod (semiconductor) inside the handle. When exposed to any light source (a fluorescent bathroom light, a plain light bulb, or sunlight), the photo-sensitive titanium rod inside Soladey converts light into negatively-charged ions (electrons). The rod releases these ions, which blend with saliva to attract positive (hydrogen) ions from the acid in the dental plaque on your teeth. The acid is then neutralized and plaque is disintegrated – a scientific approach to a cleaner and healthier mouth! Toothpaste is not required as water (saliva) is the acting ingredient – oral hygiene now becomes not only natural, but also economical! For those who find it hard to give up toothpaste, use only very small amount!