Metallics HSSCN9E Drill Bit HD Cobalt St 135d SplPt #9 3-5/8" YLW (1pc)

Yes. Cobalt high speed steel holds its edge at the higher temperatures you get drilling stainless, hardened plate, and cast iron, which is where plain HSS bits burn up. Keep the speed down and keep steady pressure so the bit stays cutting instead of work-hardening the hole.

Overall length is 3-5/8 inches, a jobber-length bit. That gives you roughly two inches of usable flute depth, which handles strut channel, box ears, panel sheet metal, and angle iron. For drilling deeper than that, or down into a pocket, you need an extended or aircraft-length bit instead.

A 135 degree split point self-centers, so the bit starts where you put it without a punch mark and without walking across sheet metal or round surfaces like conduit and strut. The flatter 135 angle also spreads the cutting load, which is what you want in hard steel. A standard 118 degree point needs a center punch and wanders more.

Yes. It is a straight shank bit, so it goes into any three-jaw keyless or keyed chuck on a cordless drill, drill press, or mag drill. There is no hex or quick-change shank on it, so it will not snap into an impact driver collet.

One bit per pack, supplied in a pouch. If you are stocking a crew or a van for 1/4-20 tap work, order quantity accordingly rather than expecting a set.

The yellow is a surface treatment over cobalt high speed steel, mainly there for identification on the shelf and in a pouch of mixed bits. The cutting performance comes from the cobalt in the steel itself, not the color, so the bit keeps cutting hard steel after the finish on the flutes polishes off with use. It can also be resharpened, though regrinding a 135 split point correctly takes a proper point grinder.