DuraVent FasNSeal W2 5" 90 Degree 316L Stainless Steel Double Wall Elbow btu104000 When installing an air kit

When installing an air kit like AKD

Porcelain liner (standard)

Part Number UBPS-30 Material Stainless Steel Width 30-Inch Height 6-Inch Depth 8-Inch Clearance 4-Inch BTU Rating 90K Weight  8 lbs Warranty

If your supply pressure is between 1/2 psig and 2 psig then you will need this second stage regulator

DuraVent FasNSeal W2 5" 90 Degree 316L Stainless Steel Double Wall Elbow btu104000 When installing an air kitFasNSeal W2 (double wall) vent lengths and components feature patented built in mechanical locking band and triple lipped directional gaskets. All pipes and components are engineered with smooth clean welds located 90 from mechanical locking bands. This construction feature allows for ease of installation. The air space between the inner and outer wall on FasNSeal W2 helps to reduce the clearance to combustibles in addition to creating a heat shield