Brand
Thicker pipe, and clearances stated
Listings state 18 inches of clearance, and the rain cap names UL 103 HT.
The rain cap fits AllFuel HST pipe only.
Everything here comes from the Amazon.com listings of the products below, read from a New York address. Where a listing is silent, the review says so. Prices move, so use the live price on each review.
A telescoping section in thick 21-gauge steel with a stated 18 inch clearance, with 49 ratings at 4.8 out of 5.
Best for: Fitting the last section between stove and ceiling box.
A thick 21-gauge 45 degree elbow for offsets around rafters, sold with a stated 18 inch clearance.
Best for: An offset to clear a rafter.
A twist-lock rain cap with a spark arrestor, UL 103 HT certified according to the listing, for AllFuel HST pipe only.
Best for: An AllFuel HST Class-A chimney.
The price beside each product is fetched as this page opens, and it is the only figure here that is current. Any amount written into the prose was read once, on the day that sentence was written, and nothing has refreshed it since.