HP LaserJet Enterprise MFP M725 series - Manual (Page 67)

Print when a toner cartridge is at estimated end of
life
Low This message displays when a supply is nearing the estimated
end of its useful life.
Very Low This message displays when a supply is at its estimated end of
useful life. Print-quality problems can occur when using a
supply that is at its estimated end of life.
ENWW Print when a toner cartridge is at estimated end of life 53