They are an older style solar panel end clamp. much more heavy duty and wasteful of aluminum than needed. This link will give you an Idea.

Those look like the end panel caps we used for office panel cubical dividers. When you reach the end of a row you would place one of these on the bottom of the panels as end bottom cap. The hole bolt and washer goes up thru the bottom They are used as a leveler. The top caps looked the same but had no hole. The Slit in the end was to slide and end panel cover, The link below will allow you to see what I am referring to. You can search here for specifics. Hope that helps.

References:

http://www.globalindustrial.com/p/storage/partitions/panels/office-partition-...

Reason:
Thank you for your response, but when I looked at the reference link, they don't look like that. Can you provide a reference link with pictures like the ones posted here?

These clips are used to hold on any camper top to a pickup. There are several styles, this is just a style. They all serve the same purpose: attach anything to the side rails to the bed of a truck.

References:

http://www.amazon.com/API-AC101P4-Mounting-Clamps-Camper/dp/B002R7VP6M

Reason:
I can't find any mounting truck clips that look like these. Could you find me an example of a closer or exact matches?

They are an older style solar panel end clamp. much more heavy duty and wasteful of aluminum than needed. This link will give you an Idea.

References:

http://sunearthinc.com/pv-mounting/pv-clamps/