These are absolutley the best radiator guards you can get for your 2017-21 EXC or XCF-W. Because one, the are full billet, thick gaurds that will never bend. Two, having fins, instead of just holes or slots is key for good air flow, just like the stock ones. And three, you can add the crossbar to them, which ties both guards together, ensuring they will never rip away from the bike. These, along with the crossbar ( sold separately ) are the best protection and airflow you can get.
These guards weigh close to 3 lbs, so it you choose being a weight weenie over the strongest protection, please don't buy these.