M2.5-0.45 X 20mm 內六角圓頭螺絲 | 圓頭內六角驅動 | 全牙 | 12.9級合金鋼熱處理黑氧化 (600個/包)

Installing these in a jig this morning and the black oxide finish is really consistent across all 600 pieces, no duds so far. The hex drive bites well with a 2mm Allen key and the 12.9 grade gives me confidence they won't snap under torque.

The 12.9 grade really shows—I torqued these into a jig with no stripping at all, and the black oxide finish makes them look clean against the tooling. Packaging was a simple box of 600, exactly what you'd expect from a bulk bag.

Finally got around to using these on a precision fixture, and the hex socket drive held up perfectly under repeated torque without stripping. The black oxide finish is a nice touch for keeping them from rusting in a humid shop.