UnderLock 3cm pavers weigh nearly 14 pounds per square foot.  The added weight makes them a preferred porcelain over some types of waterproof membrane that require a minimum of 12 pound per square foot ballast.  A 3cm paver is much stronger than a 2cm product.  A heavier porcelain is also more resistant to wind uplift.  UnderLock FS (full system) paver lockdown is an option for 3cm when added wind uplift is required.