Is the NJ0152-51X a real automatic watch?

Yes. It runs on a Citizen self-winding mechanical movement, so it winds from wrist motion and needs no battery. Expect it to run down after a day or two off the wrist unless you wind it by hand.

It is rated 5 ATM, which covers splashes, rain and hand washing but not swimming or showering. If you want pool use, look at 10 ATM or higher rivals like the Seiko 5 Sports.

How does it compare with a Seiko 5 Sports?

The Citizen is dressier with its gold case and green dial, but the Seiko 5 generally offers 10 ATM water resistance, luminous hands and a day-date. Choose the Citizen for looks, the Seiko for outdoor use.

What size is the case and bracelet?

The case is stainless steel on a matching gold-tone steel bracelet with a clasp. Check the listed case diameter and bracelet width before buying, since gold-tone links are hard to source later.

Does the dial have numbers?

No. It uses applied index markers without numerals, with a date window at 3 o'clock. That gives it a cleaner, dressier look than a numbered field watch.