Vitreous pipe: 6" heavy-grade vitreous flue pipe: various lengths availableStraight lengths can be cut (cut top only*) using a small grinder and metal cutting disc (disc available on this site). *As with all vitreous pipe the bottom end narrows to a lesser diameter to enable insertion into other pieces of pipe (male is always on top). Key reason is that any condensation that trickles down inside pipe cannot escape.