4 inch
This category focuses on 4 inch pellet and biomass venting systems and related fittings, organized so you can compare the details that affect fit. This diameter group organizes manufacturers and product lines by nominal size, helping you narrow a venting search before selecting an actual listed system.
Look beyond the product name: confirm exact nominal inside/outside size, manufacturer series, approved appliance, and connection type. A matching nominal diameter does not mean different venting families share the same joint design or approval.
- DuraVent PelletVent 4
- DuraVent PelletVent Pro 4
- Metal-Fab Pellet/Biomass 4
- Metal-Fab Premium Biomass 4
- Metal-Fab SuperFlex Chimney Liner 4
- National Chimney M-FLEX 4
- National Chimney Smoothwall 4
- Selkirk Direct-Temp Multi-Fuel 4
- Selkirk Ultimate Pellet Pipe 4
- Selkirk VP Pellet Pipe 4
- Selkirk Stainless Flexible Liner 4




