I purchased the stack robber to use as a first line to reduce sparks going up the chimney and onto the wall tent. It also retains some of the heat before it exits. The pipe stacked on top of the stack robber tends to wabble. I attach guy lines to the top of the pipe to stabilize the pipe. This product will reduce or eliminate the sparks on the roof of your tent.
Unit's overall construction is poor. The material used is adequate, however; the workmanship leaves alot to be desired. The main body is just bent and held together with a couple pop rivets. The spark arrester does not fit very well at all and its overall design makes it prone to bending and misalignment during normal use. The whole unit is prone to expelling smoke into the tent when the slightest hint of a downdraft occurs. I was so disappointed by its performance during my moose hunt, I took the unit off the stove pipe after the second evening's fire--believe me; when it's about 5 degrees outside, the last thing you want in your tent is wood smoke. By the way, I use the older version of the Alaknak Tent as a base camp and am very satisified with its performance over the past 6 years. This is the only tent that I've ever had that really breathes and doesn't sweat at all until the temperature hits about 10 degrees and even then only if you use a stove. The only improvement I would make is changing the entrance--and that you've already done. As in all things, let the buyer beware.
Use in a 10' x 14' wall tent after 3 days of vburning the spaqrk arrester on top of the pipe would clog-up and not draw. Replaced with "Stack Robber" inside tent for easier cleaning. Problem - The fitting to square box and the stove pipes are tabs that are crimped over to fasten to box and will not stand leverage of 6' of stove pipe above. Will start to come apart. Solution - Drill and steel-pop-rivet every other tab to the box, top & bottom, before it comes apart.