Existing Convertible Notes

Existing Convertible Notes. Means (i) the 6.00% Senior Convertible Notes issued pursuant to that certain amended and restated securities purchase agreement dated as of May 23, 2012 and (ii) the 3.75% Convertible Subordinated Notes issued pursuant to that certain indenture (as amended, supplemented or otherwise modified from time to time) dated as of April 6, 2011.

Existing Convertible Notes. Means Plug Power's 5.5% Convertible Senior Notes due March 15, 2023 in aggregate principal amount of $100.0 million;