502,503,504,505,508,509, 510,511,512 UTILITY FANS * note old style units had a 2 hole mounted grille - new style has centre knob mounted grille - new style is identified with a “B” suffix 13-1/2" 13-1/2" 97014186 Models 502/4/8/10/11 30110977 Models 502B/4B/8B, 510B/11B Broan grill