Woolite dryer balls are made from 100% Tibetan wool. They will not unravel and will last for years. The 2.8" diameter is optimal for fluffing and helping down or feather items dry properly.
Using a dryer ball instead of fabric softener liquids or sheets keeps fabric from becoming coated and less absorbent. That's important for bath and dish towels as drying bodies or dishes is what they do!