Description from the manufacturer: The Pro X bag has our "Excel" material on the fast side paired with our "Carpet" material on the slow side. Combined, these materials are arguably the most popular fabrics in the business, and for good reason. This bag will undoubtedly be ready to tackle any board condition! The two sides compliment each other extremely well! This bag feels great in your hand and requires little break in. The pro X is the most dangerous "Carpet" bag anywhere near the hole to date!!