The products used for scent marketing varies based on the purpose, area, and budget. Large spaces, like a shopping mall or a hotel, will require diffusers that are connected to the HVAC system. Smaller spaces can have stand-alone or wall-mounted scent diffusers. Reed diffusers and candles also can be part of the scenting process. The important part is played by the scent oil that is used in the diffusers or candle.