The firm grip has the same feel as a stock grip, it is very strong and has very good resistance to tearing and abrasion.
The soft grip is extremely soft, it gives you a very comfortable ride, great feel and reduces the chance of blisters. However, because the grip is so soft it wears quickly.
The medium is a compromise between the two.
Renthal Half-Waffle Grips
Produced by Renthal of UK