I used this for several months on a newly finished Oak floor. When I moved the mat there was damage to the floor anyway. There were scuff marks around the edges of the mat. A better solution is to buy new casters (wheels) for your chair. You will want softer wheels - that do not mark up hardwood floors.
Chair mat works exactly a designed and is good value for the money. Great for occasional use. Might go up a level if you have a stay at home office. One down side is the very sharp nub profile on the back side to hold it in place on your carpet. Use gloves when handling