These things are OK. I bought one and liked it enough for my application that I bought two more.I'm using them for engine exhaust outlets on electric generator enclosures. They keep the weather and bugs out while not restricting exhaust flow. When the gasoline engine exhaust has to push on a flap or damper to open it to let the exhaust flow out, that causes back pressure and encourages carbon monoxide build-up in the generator enclosure. That's not a problem with these because they do not restrict the exhaust flow at all.A four inch flexible pipe and this work great to channel engine exhaust out and away from the generator shelter. I use three "L' brackets with niobium magnets fastened to the semi-flexible aluminum pipe to secure the exhaust line to the muffler on the generator. This allows easy detachment to remove the generator from the enclosure for servicing. A line of Loctite red RTV high temperature adhesive sealant around the opening of the pipe that rests on the muffler makes a decent gasket/seal. All this works quite well as long as there's no restriction causing back pressure to force exhaust gasses out of the pipe where it joins the muffler. So these are a really good solution for that application.They're also competitively priced compared to metal dryer vents.Another plus is that they don't have the protruding ducting tube that dryer vents do, which makes for an easier, more compact installation in these generator enclosures. Simply insert the semi-flexible pipe into this fitting and seal it with aluminum foil ducting tape. Don't use regular duct tape, use aluminum foil tape.I think they look great. They look more professional for this kind of thing than a metal dryer vent. I mount them so that they're directed down and at a 45 degree angle away from the building the shelter sits near. That keeps the weather out and directs exhaust and noise down and away from the building. Paper wasps will nest inside this, they can't get past the screen so they build on the outside of the louvers and screen because it is a compact, sheltered area -- Exactly the kind of thing they like. What they don't like is getting gassed and cooked when the generator starts ...These things are stamped and formed metal. Like ALL such things they have very sharp edges from the manufacturing process. That's not a manufacturing defect or a quality control issue. If you cut yourself on this that's YOUR FAULT for not handling them properly. I haven't gotten so much as a nick from these, or any other stamped, formed or cut sheet metal, for a very long time. Show some good sense and you'll be fine. If you cannot handle an object like this or any other sharp object without seriously injuring yourself then DIY and handyman projects are not for you. If that's the case go hire someone who won't lose a finger on a simple piece of hardware.