What height should I buy? Good question. What is likely to cause the damage? A load, a pallet truck, the counterweight of a forklift, the forklift forks, or something else.  If operators are driving safely then the loads and forks are close to the floor; indoor counterbalanced forklifts, straddle lifts, and reach trucks have low ground clearances typically 4" or less. Many loads today are stacked beyond the confines of the pallet, so perhaps the product being moved becomes the contact point. If it's tailswing from the forklift, you need to invest in more operator training! There's not much thaty withstand pounding from those beasts. Every operation is different, a walk thru the warehouse will likely point to your solution.