Channel Stone Setting Practice Ring, includes 2.5mm CZThis item ships directly from Pepetools and may ship separately from the rest of your order. Separate shipping charges may occur. Channel setting for 2. 5mm stones. Includes 2. 5mm Round Cubic Zirconia Stones to set. Cast in Bronze which mimics harder karat golds and reduces cost. 3 on the Moh scale with higher karat golds being 3 4. Dimensions Inside Diameter 19. 5MM Outside Diameter 24MM Width 6. 5MM Includes 28 practice CZ's in 2. 5mm, to purchase