Either they're so intuitively obvious what they are, nobody is replying or...
Nobody has ever seen these magnificant connectors that look like they can take 50 amps and have a slide connector on each side so you can fasten them together.
I think its intuitively obvious, but I'll say it anyway. Those are anderson powerpoles. Looks like 75A version I believe.
http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/pp75-red-black-75-amp.html