Twin wall flue system design, type of single skin stove flue pipe

There are two types of single skin flue pipe to choose from:
Stainless steel flue pipe 316 grade stainless steel flue pipe comes in a stainless - silver - finish. The advantages are that it will last longer than enamelled flue pipe, fits better with the double skin flue adapters, and can be sprayed to match the stove (black enamelled flue pipe will be a different colour black to stove). The disadvantage is that it can cost slightly more.

Black enamelled flue pipe Enamelled steel flue pipe comes in a black finish and usually works out slightly cheaper.