InvictaPro Diver Stainless Steel Men's Automatic Watch - 40mm

Can somebody please tell me the difference between an Invicta Pro Diver Men's watch 8926 at £62 and the 8926OB model at £76.95. Thank you.

Does this watch come with a gaunrantee and does it come with a leather strap or can you get one with a leather strap.

How long does the watch stay wound for when not worn?

Can anyone tell me the process to hand wind the automatic Invicta 8926OB awatch?