I'm not even sure they're related, but I think they are, because that's how they packed other stuff.

It looks like some type of pulley set up, as the 2 black barrel shape things fit perfectly in between the thing that looks like a hose reel.
Size wise it looks like the 2 bolts then go through the center of the barrel to hold them in position.

the word for the barrel/cylindrical part escapes me right now... center rod, stem...