This tandem dolly works very well.  It makes taking out the trash so much easier.  It comes in a huge box fully assembled, and is quite hefty and sturdy.  I load my Brute trash cans on them and roll them to the curb.  The dolly can fold, but not fold flat.  You basically can stack your Brute cans on one side, and then flip the other side up and have it stand 90 degrees.  This allows you to roll your empty cans and push them against the wall.