Manufacturer page.

The Sterling & Storm hinges consist of a left hand and a right hinge to form a pair. Additional features include - They are assembled with a number of unique features that include a composite slider, asymetric end points and caps, integral limit stops, balancing geometry and strengthened links resistant to abuse loads - Product is capable of carrying vents up to 3m high & 250kg top hung or 838mm wide & 47kg side hung -Hinges provide opening up to 50° top hung and 90° side hung but can be restricted to smaller openings if required. The hinges can also be used in bottom-hung mode for purge ventilation