Product review (2 stars): Good design, bad assembly
First, it's a really great idea.

But it fails on assembly where they link the round sheet metal to the flat sheet metal.  It's not quite spot welds and not quite crimped together.  It's sort of crimped together.  Very little pressure will separate the rings from the metal housing.

It's easily fixed with a few rivets but it's a cheap, half-arsed design.

They were nice enough to put a sticker on to say which side goes to the dryer output.  Which is VERY odd since this thing is actually two halves of the same piece slid together.  Maybe they think that because air is flowing in a certain direction it won't escape out the gaps in the metal.  Realistically, once this thing is connected you should use foil tape to cover the gap at the slip joint.

So you'll need this, clamps, foil tape, and a delicate touch.  I ended up using flexible hose and accepted that the dryer would be 6 inches from the wall.