High quality brass thread adapter M8 to M4 / M6 / M8 / M10 / M12, set of 4 | eBay
Amazon.com: WHY-YUE 1Pcs M8 M10 M12 M14 M16 M18 M20 Metric Female to Male Thread Brass Pipe Fitting Adapter Connector for Air Water (Size : F M10x1-M M10x1.5) : Tools & Home