This cap can solve two problems:
1) Negative house pressures can pull the smoke from one flue down another flue right beside it. Adding the flue Stretcher to the upstairs flue distances its smoke from the downward pull of the downstairs flue.
2) By raising the height of a flue above nearby roofs or structures you wiil improve draft and reduce downdrafts.
Theses caps come in stainless steel and copper, in 1' and 2' heights. Theses chimney caps tighten with screws and wind tests have proven that this mounting system holds tight.
Made by Olympia in the USA with a lifetime warranty and ships free and guaranteed price.