This is a vintage antique British Seagull antique outboard motor transom clamp assembly.  Smallest size in bronze with stainless pin and stainless screws and pads. This came from EFPC which is the 2-3hp size but it should fit the 40 minus and 40 plus models as well. Possible others.  The clamp screws are slightly bent which limits the extreme opening size.  It will still fit most transoms. You can straighten the screws with heat and a soft head hammer. When these clamps are missing, as often happens, the outboard is useless.  They are easy to detach and often stay with the boat when it is sold separately from the engine.  If you need this part don't hesitate.  British SeaGull is long out of business and the remaining parts are drying up.   Look at the photos and email with questions.  Thanks for looking.