Ofna jammin roll bar help

Hi there,
i was checking out the ofna pro team tips on the jammin website and i saw this roll bar design that looked great, however i don't know where to get fittings/connections like the ones in the photos. Just wondering if anyone knows where i can purchase them from or more importantly what they are commonly called so i can search for them on the net?

I'm hoping they are not a custom job, so i thought i'd ask.