Note E: Other Rare Earths shall be principally heavy rare earths, for
example, Gadolinium, Dysprosium, Erbium, and Ytterbium. Other Rare
Earths are derived from the Yttrium, typically 80 % Yttrium 20 %
heavy rare earths.Note F: Zinc + Silver content shall not exceed 0.20 % in WE43B.