Is the Invicta Pro Diver 8928OB a real automatic watch?

Yes. It uses the Seiko NH35A automatic movement, which winds from wrist motion and can also be hand-wound. It has no battery.

Can you swim with it?

Yes. It is rated to 200m with a screw-down crown, so swimming and snorkeling are fine. Have the crown and gaskets checked before diving.

How does it compare with the Rolex Submariner it resembles?

It copies the Submariner look, but uses a mineral crystal, gold plating and a basic bracelet instead of sapphire, solid gold and finer finishing. It is a homage, not a substitute.

What size wrists does the 40mm case fit?

The 40mm case suits most wrists, roughly 6 to 8 inches. The 14mm thickness makes it sit tall, and the bracelet can be sized with removable links.

Does it have a sapphire crystal?

No. It uses a mineral crystal, which is more prone to scratches than sapphire. Some owners replace it with an aftermarket sapphire.

What comes in the box?

The watch on its two-tone stainless steel bracelet, usually in an Invicta presentation box with a manual. A yellow Invicta dive box is common with this model.