M3 x 4mm 杯端內六角止付螺絲 | 合金鋼鍍鋅（1000入/包）

I've gone through almost the whole bag of these on a tight gearbox rebuild and not one stripped or snapped. The cup point grips the shaft far better than a flat tip, which made all the difference in a spot with barely any clearance.

The hex socket drive really saved me when I was torquing these into a tight bracket where a normal Allen key wouldn't fit. Cup point bit in nicely without stripping, and the zinc coating looks clean. Bag of a thousand means I’m set for years.

I needed a whole bag of these for a small robotics project, and the cup point tip really bites down securely without slipping. They’re exactly the right size for tight spaces, and the zinc plating is a nice bonus for preventing rust.