Amazon.co.jp: Fittings - 1pc M8 M10 M12 M14 M18 M18 M20 Metric Female to Male Threaded Brass Pipe Fitting Adapter Connector for Air Water Home, Factory and More (Size F M14x1.5-M M16x1.5) :
Amazon.com: Vicma Mirror Thread Adapter converts M8 Left-Hand to Work with M10 Left-Hand Mirror Mount : Automotive
XQSMWF 5Pcs Thread Screw Sleeve Conversion Nut for M10 10mm Male to M8 8mm Female, Bolt Sleeve Nut Thread Screw Fitting Reducer Adapter: Amazon.com: Industrial & Scientific
Amazon.co.jp: レデューサメトリックm10 m10 X 1.0オスto m8 m8 X 1メスヘッドレスアダプタ(2単位) : 産業・研究開発用品
Pack of 1 x M10 to M8 ZINC Fully Threaded Reducer/Connector : Amazon.co.uk: DIY & Tools
MECCANIXITY Thread Reducing Nuts Insert M10 x 1mm Male to M8 x 1mm Female Adapters 10mm Long Pipe Fitting Conversion Sleeve Reducer, Pack of 6: Amazon.com: Industrial & Scientific
MECCANIXITY Thread Reducing Nuts Insert M10 x 1mm Male to M8 x 1mm Female Brass Adapters 10mm Long Pipe Fitting Conversion Sleeve Reducer, Pack of 3: Amazon.com: Industrial & Scientific
Amazon.com: MECCANIXITY Thread Reducing Nuts Insert M10 Male to M8 Female Adapters 10mm Long Pipe Fitting Conversion Sleeve Reducer, Pack of 5 : Industrial & Scientific