Grading overview Look at the Sport grading overview and find out how BOEN Sport selects the grading for your surface. Download here the Sport Grading Explanation: BOEN Sport Boflex Stadium Gradings BOEN Sport Boflex Olympia Gradings BOEN Sport Actiflec Stadium Gradings BOEN Sport 14 mm Gradings BOEN Sport 21 mm Gradings BOEN Sport 23 mm Gradings