This is a Nikon Nikkor 400mm IF-ED f/2.8 MANUAL FOCUS ONLY telephoto lens. This version of the 400/2.8 was the earliest version made by Nikon. They made this version from 1985 through 2002. The serial number on this one indicates that it's pretty early in the manufacturing run. Serial numbers started with 200001 and this one is (US) 200503.
The glass is in decent shape. There are no marks on the rear element and there is one mark on the front element (see photos). There is no haze or fungus inside but there is some dust. The biggest issue is that an internal lens segment is loose. You can hear something heavy clunk inside as you tilt the lens up or down. I put it on a camera body and while the focus ring turns freely, nothing happens inside the lens when you turn that ring. This lens needs to be disassembled and have the internal focus mechanism repaired. This is a US serial number, so if you want Nikon USA to fix it, they will service this lens.
This auction comes with the lens, a Nikon lens strap, the CT-400 hard case (which is in good shape despite a ton of tape on the outside) and the slip-in or drop-in 52mm gelatin filter holder. The built-in lens hood is intact and works freely.
Please take a look at the photos and email with any questions.