Important: The wall thickness of my stainless steel tubes is 74% greater than the Lopi factory-made stainless steel replacement tubes. Thicker tube walls mean longer life. Do it once and do it right! This listing is for a stainless steel secondary air tube replacement kit for Lopi Endeavor, Endeavor 380-NT, Republic, & 1750 wood burning stoves, and for Lopi 1750, Revere, & Revere X-NT fireplace inserts. This kit is only for the above-mentioned models manufactured up to and including year 2019. Replaces Travis Industries / Lopi part number 98900233. Although a bit lengthy, please read the entire listing.. This kit includes the following: three stainless steel perforated tubes, three steel collars, and six stainless steel spring pins. I have owned a Lopi Endeavor stove for 17 years. It is a fantastic stove. There are three secondary air tubes in the top of the firebox, just below the baffle. These tubes introduce secondary combustion air through perforations in the tubes, which allows for more complete burning and increased heat output. However, these tubes will eventually fail (crack and bend) and require replacement. The tubes are type 304L, heavy-wall stainless steel pipe. I include six stainless steel spring pins in the kit (each tube takes two pins) – my experience has been that the original plain steel spring pins lose their “springiness” over the years. I suppose this is due to the many cycles of high heat and cool-down in the firebox. Also included in the kit are three steel sliding collars which, in conjunction with the spring pins, keep the tubes locked in proper alignment. Here are some examples of feedback that my secondary air tube customers have left for me: Well made, and custom collars worked perfectly. Thank you Kris As described and arrived quickly. Items better quality than what came with original stove! Thanks for the customer service! Good attention to details, Courteous and Responsive. Thanks for the amazing speed! Installation is not difficult. You will need a hammer, vice-grips (7″ size works great), long-nosed pliers, and possibly a 1/4″ punch. Make note of the orientation of the perforations on each tube – the middle and rear tubes are the same, having 1/8″ perforations that face straight forward, while the front tube has 3/16″ perforations that face forward, but pointing down at a 45 degree angle. Use the vice-grips to grasp, twist, and pull out the old spring pins. If there isn’t enough pin sticking out to get the pliers on, you can use a punch and hammer to drive them up into the tubes. Slide the collar to the left an inch or so, lower the right side of the tube so that it clears the short pipe stub on the right, and pull loose from the welded socket on the left. Slide the new collar over the new tube, insert the left end of the tube into the welded socket on the left, and slide the collar to the right, over the short pipe stub. Use the closed long-nose pliers to line up the right-hand hole in the sliding collar with the hole in the short pipe stub on the right (a common #2 phillips screwdriver also works well for this). Use the vice-grips to grasp the spring pin (see helpful hint below), and use the hammer to tap it into the hole that you just lined up. Be sure to keep the spring pin straight. The spring pin can be a bit difficult to start in the pipe stub, but it will go in, so stick with it. After you get the spring pin started in the hole in the pipe stub, drive it in with the hammer until about 1/4 or so is still exposed. Now center the left hole in the sliding collar with the hole in the air tube, and install the spring pin in the same manner. Shovel out the ashes from the firebox before installing the new tubes. Trying to find a dropped spring pin in the ashes is like trying to find your car keys that you dropped in the snow. The holes in the sliding collars are slightly larger than the spring pin holes in the tubes – the spring pin does not fit tightly in the sliding collar holes. Note that the spring pins have a slot down one side. When installing the spring pins, if you put the jaws of the vice-grips on either side of the slot and squeeze the slot shut, it will hammer in much easier. Don’t get carried away with the vice-grips… Use just enough pressure to close the slot. You don’t want to deform the spring pin with too much pressure. If you have to punch the old spring pin up into the pipe stub, it can be retrieved with long-nose pliers. Or, you can just push it into the secondary air duct, where it will lay harmlessly for the life of the stove. If you wear bifocals like I do, you may find it helpful to lay crossways in front of the stove (on you left shoulder, if you are right-handed) to do the work. Disregard this helpful hint if you can tip your head way farther back than I can, in order to focus properly! USERS’ USE OF THE PRODUCT IS AT THEIR SOLE RISK.