In one narration of Ahmad the wording is: Concerning the iron ring, the Prophet (peace and blessings be upon him) said: "This is the ornament of the people of Hell." The narrators of one of Ahmad's two chains are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب اللباس / 8722