What this LARGE LENS is?

On the very bottom… The one that says, "VANGUARD"…

Vanguard is a name put onto a lot of photo products that do not cost a lot.
Looks like the 400mm lens could be longer telephoto however.

Looks like some telephoto lens, a really cheap looking lens.

I've seen those vangard lenses be around 1200mm or 1600mm at f/8
Yes they look cheap. They aren't horribly expensive for what you are getting. They are manual focus lenses. But you get an insane focal length.

Looks like a cheap f/8 or f/11 telephoto lens to me.

Basically a toy/recreational telescope converted for SLR use.