Engagement Ring Mounting-Steven Kretchmer™™™s Tension-Set™™®™ Yellow 18 Karat R3.2Mm Engagement Ring Size 6.5. Description Is For The Mounting Only. Complete Your Ring With The Center Diamond Of Your Choice. (Image shows both 18 kt and Plat rings, in store sample is in 18 kt yellow gold and pricing is for 18 kt.)