This is a manually-focused Nikon Series E 50mm f1.8 "pancake" lens with an AIs mount, originally sold circa 1981-5 as a kit lens for manual focus 35mm cameras, and often rated as the best of the Series E lenses. On compatible Nikon bodies it offers open aperture metering; on other bodies stop-down metering or bracketing exposure will usually give good results, and focus confirmation will work using the symbols at the bottom left of the viewfinder display. It has front and rear caps, a UV filter, a polarizing filter and a cloth storage pouch. At 50mm it's a standard lens for a 35mm SLR, a portrait lens for a digital camera with an APS-C sensor. It ought to be useful for portraiture and macro work.

This is mechanically and cosmetically good, optically about average, with some internal dust that may be an early stage of fungus; it doesn't seem to be degrading image quality significantly. Focusing and stop down work well, and there are no significant marks or damage to the paint apart from slight wear to the edges of the focus and aperture rings from putting it in and out of a case or pouch.

I tested it on a moderately cloudy afternoon using a Nikon D7000, which has full metering support for AIs lenses. The camera was set to ISO 1600, with the lens iris set to f8 for all shots.
Church 230 yards 1/6400th f8
Tree 30 yards 1/4000th f8
Garden (bird bath 17 yards) 1/400th
Coin and brick bits 7ft 1/800th f8
Plant on edge of roof 11ft 1/640th f8
Coin in closeup about 20" 1/640th F8

There are reviews on these sites:
https://casualphotophile.com/2019/10/29/nikon-series-e-50mm-lens-review/
https://matthewdurrphotography.com/2012/06/23/lens-review-nikon-50mm-f1-8-series-e/
https://www.kenrockwell.com/nikon/50f18E.htm

As always I'm starting low and with no reserve. I'm separately selling some other photographic items. If you buy multiple items from me please request a combined postage invoice, I'll do my best to get it down to the lowest possible price. I do not make any profit on postage. Postal prices rose at the end of March.

International buyers: The postage price shown is based on an estimate of packed weight, around 280g. This will be sent by a tracked postal service; if multiple items are sent (max 2kg total packed weight) the tracking applies to the whole package and works out cheaper per item. Please note that eBay will add VAT or sales tax to the final price in the EU and some other countries.