AQ-3000s help

[Miller Aquatic]

So I bought a tank from someone and he threw in a used skimmer for me and I’ve never had a skimmer of this dimension before. It’s an octopus 202s classic skimmer. I don’t know if this is everything I would need for the pump? The pictures I see it looks different. Since this thing was used I’ve been soaking it in white viniger

 

[Miller Aquatic]

The other part of it is this but it’s not connect like in the picture could it be just an older design?