The Harvia WHP1000M steel chimney extension made of black powder coated steel enables you to easily extend your Harvia steel chimney. Thanks to an ingenious joint mechanism, the supplementary parts are wound together and the smoke pipes are locked in place by the grooves on them. This prevents movement caused by temperature changes. Indoors, the chimney can be installed up to a height of 3 meters without support. Outdoors, the corresponding self-supported installation height is 2 meters. Interior – Wet Area. However, if the goods are out of stock and we are waiting for new stock to arrive, it may take us one to two weeks to replenish supplies. If you have any technical questions, feel free to ask, we will reply within 24 hours, except for weekends.