Casio Men's GW-M5610-1BJF G-Shock Solar Digital Multi Band 6 Black Watch

why is this one so much more the the none negative one ?

I got the watch and the model number is 3495 (on the back). the product picture on amazon says 3159. did i get the wrong watch?

Is there a button for the backlight or is auto the only option to light it up?

Is this watch real? Aka not a knock off