M6-1 x 12mm 內六角螺絲 | 內六角驅動 | 全牙 | 8.8級合金鋼熱處理黑氧化物 (600入)

Was slightly worried about surface rust on black oxide fasteners, but these arrived dry and uniform in color with no flaking. The hex sockets were clean and engaged a 4mm allen key snugly right out of the bag. For the price per piece, they’re a solid buy for jig building and fixture plates.

Thread engagement on these is excellent—every screw seated perfectly in my fixture plate without any wobble. The black oxide finish seems durable and adds a nice, professional look to the assembly.

Used these for a jig I was building and the black oxide finish made them easy to handle without slipping. All 600 screws were cleanly threaded and consistent in length.