DuraVent FasNSeal W2 6" 23 Degree 29-4C Stainless Steel Double Wall Bird Screen w17.75 Flexible liner is particularly useful

Flexible liner is particularly useful when the masonry chimney has one or more deviations

and unattractive

Vent-Free gas fireplaces

so it won't be moving incredibly hot air around

36" Vent-Free Regular Firebox

DuraVent FasNSeal W2 6" 23 Degree 29-4C Stainless Steel Double Wall Bird Screen w17.75 Flexible liner is particularly usefulFasNSeal 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