If you are just starting out with essential oils or trying to find the perfect gift for your oily friends without spending a fortune, this is the perfect diffuser for you! The Scent Ball Plug-In Wall Diffuser is designed to make it as easy as possible for you to experience aromatherapy! Just add 2-3 drops of essential oil to the pad and insert into the diffuser. The oil pad can be reused until it begins to discolor. Comes with 5 refill pads.