M4 中型開口彈簧墊圈 | 鋼鍍鋅 (2000 / 包)

Used a handful to secure a small motor mount and they held tight after an hour of runtime. The zinc plating looks even and should resist rust plenty well in my tool shed.

The zinc coating looks clean and consistent across all 2000 pieces, which is exactly what I needed for a batch of outdoor mounts. They bite into the steel nicely under torque and have held firm through a week of heavy machine vibration.

Put these on a bracket that kept rattling loose on my CNC router—hasn't budged since. The zinc coating is nice and even, no rough edges. Exactly what I needed for vibration-prone spots.