The 4" Adjustable Roof Flashing is fabricated of galvalume. It is adjustable to the pitch of your roof from 0/12 - 6/12 pitch. A Storm Collar is also required. Roof Flashing and the required Storm Collar work together for a weather proof seal. As with all of our B Vent components, it can be used with natural gas or liquid propane, Category 1 appliances.
The interior dimension is 4 5/8".