OD: 8/10/11/12/14/15/18/20MM Cup Core Plug Zinc Plated Engine Expansion Replace
Size: OD:8/10/11/12/14/15/18/20MM. Finish: Zinc Plated. Durable Zinc Plated. Plug that prevents the engine block or cylinder head from cracking in case of freezing coolant. Also used to plug the casting holes from production.