From the Manufacturer's Label:
Refills and recharges for Aromatherapy diffusers.
Refill pads to fit the following products:
Aromatherapy ""Scentball"" Plug In Diffuser
Aromatherapy ""CarScenter"" Car Diffuser
Aromatherapy ""MIO"" Battery Operated Portable Diffuser
Simply apply the specified number of drops of your favorite essential oil or blend of oils on to the reversible pad and insert into the diffuser.
A refill pad may be used until it hardens and or discolors.