MIST MAKER COMES WITH A CERAMIC DISK WHICH PRODUCES THE MIST. THE MOST COMMON CAUSE OF A FOGGER UNIT NOT WORKING CORRECTLY IS A USED-UP DISK. WHEN YOU SEE THE MIST OUTPUT LEVEL START TO DIMINISH IT'S TIME TO REPLACE YOUR DISK, (IT IS THE THE PART LOCATED AT THE CENTER OF THE MIST MAKER). DISC ONLY.