M G Duravent 3PVP-TADX4B Dura-Vent PelletVent Pro black 4 Inch tee adaptor with increaser and 3 Inch branch Laser-welded, double-wall pipe with a .012" inner wall of 444 Stainless steel Outer wall of .018" laser welded Galvalume Encapsulated O-ring gives secondary seal to system. 1" clearance to combustibles in the US and Canada. Black, built in appliance adapter and increaser for compact applications.