بسم الله الرحمن الرحيم
Majority of Islamic Jurists (fuqaha) are of the view that men can only wear silver ring except gold, and other metals. And this silver ring should also not exceed more than 4 gram 374 milligram in weight. As far as the matter of wearing chain is concerned, it is not allowable to wear the chain of any metal for beauty. In case it is the chain of a watch then it should not be made of gold and silver rather it should be made of any other metal. Likewise if a chain is worn to keep the blood pressure in control for the purpose of treatment then it is allowable but that too should not be made of silver and gold rather it should be made of other metal.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.