These Irish eight nickel plated handcuffs (SMALL) are based on the classic design so named for the obvious reason that they look like a figure of eight.  The 'cuff on the hinged side is 54mm wide and 46mm from the centre to the outside.  The other cuff is about the same from the lock cylinder to the centre but 59mm wide.  They weigh 392 grams.  If you prefer imperial measurements you will find a really good conversion site at http://www.onlineconversion.com/weight_common.htm.  They come supplied with one screw in key.