It works on all cylindrical vents regardless of what they’re hooked up to.
Yes, Home Depot sells packages of extension rods I think by a different manufacturer, but they work with this set. IMPORTANT NOTE: Be sure to securely tape all the joints so they don't unscrew when you reverse your drill to remove the cleaner from your duct.
Yes to the first question. They are on the web site in case your store doesn't carry them. It is a different company but they screw together I think it comes with six 3' sections.
Yes, they are sold on line - i think a set of 4 four foot sections on the same page online.
Yes, I purchased additional, you can make it as long as you need.
According to the Home Depot site there are two versions of this product, the one pictured here is 8 ft and this https://www.homedepot.com/p/Everbilt-Dryer-Vent-Cleaning-Kit-DVBRUSHK-10RHD/205047060. This is a 12 ft version, come with six 2’ extensions and is Cheaper! No separate extension rods are available at HD. Maybe direct from the company?
Yes they do. Instead of a second package, HD carries extra rods (I think another manufacturer) that gives you 6 rods for another 18 feet. CAUTION: Just be sure to securely tape (like shipping tape) the connections together so they don't come apart when the drill is in reverse, otherwise you may not be able to retrieve the brush from the vent duct.
Unfortunately, you will need to buy multiple kits to get beyond 8'.
Plastic. Be careful.
Don’t use it with any flex duct. It’s suitable and designed to work with rigid sheet metal and PVC/ ABS ducting only.