Explain for purity of Rare Earth Metal：what is the purity of Rare Earth Metal? Whats mean is “TREM”? Whats means is the “RE/TREM”? TREM means Total content of Rare Earth Metal, RE/TREM means this RE element's content in the Total content of Rare Earth Metal; for example La/TREM: 99.9%, TREM: 99%, means La element content is 99.9% in the total content of Rare Earth Metal and Total content of Rare Earth Metal is 99%.