M4-0.7 X 20mm 內六角螺絲 | 低頭內六角驅動 | 全牙 | 10.9級合金鋼熱處理黑氧化 (400 / 包)

The threading is crisp across every single one, so they drive in smoothly without any binding. I've been using them for a small jig build and the black oxide finish looks sharp while holding up well.

These arrived with a clean, consistent thread cut that made them a pleasure to drive into my fixture plate. The black oxide finish feels durable and hasn't shown any visible wear after repeated assembly cycles.

I’ve been using these in a jig I’m building and the 10.9 alloy steel feels properly tough—no stripped heads or bent shafts after a lot of tightening. The low profile heads sit flush in tight spots, which is exactly what I needed.