VEVOR Cable Railing Post, 36" x 1.5" x 1.5" Steel Level Deck Railing Post Without Holes, SUS304 Stainless Steel Cable Rail Post, Stair Handrail Post for DIY, 1-Pack, Black

The product description states it is suitable for outdoor use. The stainless steel construction with black powder coating resist corrosion and rust, making the cable railing post durable for outdoor installation.

Yes, the cable railing post can be mounted on angled stairs. Its 0-300 degree rotating cast bracket allows it to shift to different angles for installation on stairs.

Yes, drilling is required for installation. The product description states, "Free Drilled Hole: The number of holes and the distance between hole to hole can be adjustable to give you diversity in the jobs it can complete. With the help of measurement instruments is better. When drilling, leveled holes and inclined holes are both available."

You’d have To cut off the top and cap the cut with something else that made it look factory

The only way it could be shortened is if you cut it off and re-weld it

The cable is your choice. This is non-porous, you need to drill your own holes, and normal spacing is 0.6 meters.