What is this?? And how does it work?

Hey guys so I don't have the full tool kit but even if I did how does this thing hokd the tool kit? I pulled it out of an ex cab thinking it was stock for all models but I have no idea if anyone has one will you post how your tool kit is mounted?

 

Bump??? Anyone

 

Will the jack itself fit 'under / into' the bracket? If it does, then hold it in place and extend the jack until the bracket 'holds' the jack. Though, it looks to me that the wingnut would be in the way. I have an extended cab and a similar bracket secures the jack in a similar method...

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