These come in two varieties: natural cork, and a black rubbery foam mixed with cork.
Cork grips absorb shock and don't get slippery. They are nicely shaped to fit your hand and very comfortable. Perfect for your city bike or classy mountain bike. Fits standard 22.2mm (grip area) bars only.
If these or any grips fit too loosely on your bars, put a bit of tape on the bar first. Any tape will do, electrical, duct, athletic, Tressostar.