knurled

Relating to case goods and cabinetry in the kitchen and bath, elements such as ribbing and knurled hardware remain popular.

Whatever you use them for, you’ll be doing it in style; the knobs are colorful and knurled at the top, which should help you grip something that’s otherwise approximately the size of a large Q-Tip.

It has knurled wheels and dials.

There's "an object bearing a knurled, rounded metallic-colored end with a black face, a large hole, and an apparent screw head, bearing a strong resemblance to the Microtech SBD Dagger," said the note.

Maybe one of those bumpy, knurled massage balls?