The Himalia nebulizer diffuser is used with a USB or mains connection . It does not require water, so no maintenance. 1 empty 10ml bottle is included to allow you to create your own synergies. Back to basics with this nebulizing diffuser for an optimal use of essential oils ! Nebulisation is the diffusion of pure essential oil (no water) by drawing it directly from the bottle (it works with 5ml, 10 ml, 20 ml, 30 ml bottles). It therefore makes it possible to enjoy from the beneficits of essential oils in the most efficient and pure way ! It also offers « zero maintenance » because there is no water, so no limestone or fur.