M20-2.5 x 340mm 內六角螺絲 | 內六角驅動 | 部分螺紋 | 12.9級合金鋼熱處理黑色氧化 (2 / 包)

The black oxide finish on these feels properly done, not just a cheap paint job, and the hex socket drive seated perfectly on my torque wrench. Class 12.9 is no joke—these M20s handled a heavy press fixture without a hint of flex. Exactly what I needed for a precision assembly rebuild.

Installed these on a custom jig frame and the partially threaded design made alignment much easier than expected. The black oxide finish seems nicely uniform and durable so far.

The hex socket drive on these M20 screws made installation a breeze on my jig setup, and the 12.9 alloy steel feels incredibly sturdy. The thermal black oxide finish looks clean and professional too. Exactly what I needed for heavy-duty tooling work.