This is a swing corner bracket, a heavy duty pre-manufactured metal corner bracket for a garden swing. Made from powder coated steel tubes, designed to hold 100mm timber machine round poles during the construction of a DIY Swing frame. The steel has a thickness of approximately 2.5mm with bore holes for fixing screws with a diameter of 10mm. Right angled from the top pole to the two pole legs, (with a 60 degree angle between the downwards facing legs – see diagram).
These are sold a single item so one of these would do one corner.