LL BUILDING PRODUCTS F6IFD4X300 Duct Pipe, 4" x 25'

Ducts that are made from plastic can tend to be very fragile. I was thrilled to discover that this duct is made from a very strong plastic. The only time that it ripped was when I was connecting it to my metal vent to outdoors -- and this was due to it getting snagged on the vent's VERY sharp and jagged seam (i.e., my fault) -- I simply covered the jagged seam with a piece of foil HVAC tape, cut off the few inches that ripped, and reattached the duct.Instead of tearing, the plastic tends to stretch, similar to a high-quality trash bag. This feature makes installing it a breeze. Very happy that I picked this product.

The flex duct works very good for fan venting and it is easy to work with. The company that sent it was on time and very well packed.

This worked really well. I needed a short run between a bathroom fan and 4" roof vent, it worked really well. The material was surprisingly durable. The material was easy to work with. The key to success is making sure the outer sleeve is long enough to completely cover the clamp. That is, don't cut the inner casing longer than the insulation layer.I used these clamps: https://www.amazon.com/gp/product/B001DDY6HG/ref=cm_cr_ryp_prd_ttl_sol_20However, a long zip tie (like 14" long) could have done the job well, I believe.

Let me first say, the 4" duct is extremely hard to find. I looked at several home improvement store and came up empty. I finally found the duct on Amazon. The product is exactly what I needed. It seems well made for a non rigid duct, that being said, I did not want a rigid duct. The duct was easy to work with and made the job a lot easier. Word of advice; if you are using this in your attic as I did, cutting and prefabricating the correct duct BEFORE you install makes thing go a lot smoother.

Pretty simple product, but it's doing exactly what I wanted it to do. I have to run a fresh air vent through a living space. This is a major improvement over the uninsulated one I was using before. Thanks!

Good high quality insulated duct. No issues noted. Used this to connect two bathroom ventilation fans to roof caps.

This ducting is great. What a big difference over using standard dryer ducting. This insulated ducting also considerably cuts the sound of my ventilation system by at least 1/2; you could barely hear anyone talking over the loud fan/air resistance before, once all the ventilation was connected it brought it to a low hum. Using it to pull cold air from outside into a greenhouse. The temperatures differed so greatly (19f to 76f) condensation was starting to drip from the generic ducting also raising the humidity up quite a bit. Since installation, no condensation is anywhere to be found. Also the temperature coming in from outside is also kept colder while it travels.

I am trying to sell it on Craig's list. I decided to use solid metal and wrap them if I need it this winter.