Stack for old model 28000 Big Buck, Buck Stoves. Stack fits openings 16″ x 3-3/4″ or openings of 13-3/4″ x 3-3/4″. The gasket on the bottom allows it to fit both sizes.

This stack should also fit the small and regular Buck, it is the same as the regular stack except it has 2-1/2 flange extensions welded on both sides.

Outer measures 20″ x 4.5″