This helps remove the slapping noise during cold start, common place among engines running forged pistons due to larger then OE bore clearances. The crowns of the pistons are also polished to better resist detonation on a high performance engine. Polishing allows a more even spread of heat inside the chamber. Image is a Stock image. Any Items That Are Out Of Stock Or have Extended Lead Times, May Take Slightly Longer Than Normal.This item is in the category "Vehicle Parts & Accessories\Car Parts & Accessories\Engines & Engine Parts\Other Engine Parts". The seller is "shopbhp" and is located in this country: GB. This item can be shipped worldwide.