Adesso MRP-16CD-TR - 16-Inch Cash Drawer Tray Insert for Cash Register

How much does this item weigh?

Are there under-counter mounting brackets for this register? I can't find any.

Is this compatible with Square?

Can this unit be opened, just with a turn of the key? Or,do u have to lift it up& open from underneath? That is, if you dont have/want the pos system