M20-2.5 X 65mm 內六角螺絲 | 平頭六角驅動 | 全牙 | Class 12.9 合金鋼鍍鋅 (25顆/包)

The flat heads sit perfectly flush in my jig plate, making setups cleaner than with button heads. Took a lot of torque with a hex key and no stripping—these class 12.9 screws are tough. Exactly what I needed for precise assemblies.

Used them to secure a heavy fixture on my milling table and the 12.9 grade steel held perfectly with no flex. The hex drive seated easily, and the zinc coating looks clean.

Installed a set of these in a jig I'm building for a production run, and the 12.9 grade alloy steel feels much more robust than the standard 8.8 I used before. The hex socket drive seated cleanly with no stripping worries.