Grizzly 13 x 9 - Rectangle. Size 13 x 9 Part # 7G913
Grizzly 12 x 9 - Rectangle. Size 12 x 9 Part # 7G912
Derco Inc was based out of Michigan and eventually became the line of stoves know as Grizzly. No other information is available, but if you have a different Derco or Grizzly glass size, let us know and we will be able to make it for you.