Genuine Ebony Piano Sharps 2 Sizes to choose from:

The preferred choice for high end grand pianos.
386 - 3-3/4" long - Height .550"
386A - 3-3/4" long - Height .595"
Sold per piece

Real ebony sharps are the original black keys - solid ebony wood, not plastic. For centuries pianos were built with ivory naturals and ebony sharps because ebony is:
Very dense and close-grained - doesn't wear into grooves like plastic
Slightly porous - gives you grip when your fingers get warm, unlike glossy plastic that gets slippery
Deep black with subtle grain - not pure jet-black. If you look close, real ebony shows brown/black wood grain, especially on the side.

How to tell if yours are real:
Look at the side - real ebony shows wood grain, plastic shows mold line. Feel the top - wood is warm and slightly soft to touch, plastic is cold and glassy.

Most pianos before ∼1960-70 used real ebony; after that manufacturers switched to plastic for cost. If your piano is described as "Ebony wood sharps, natural materials" like a Kayserburg or other hand-built model, that's real wood
Real solid ebony is now a specialty item & not sold by big-box stores:

If you're restoring a vintage instrument and want to keep it authentic, these are the sharps for you.
If you just need functional, durable replacements for a modern player, the plastic sets work fine and are scratch-resistant.