Universal Fan Fileter F-101
DESIGNED TO FILTER OUT THE BUZZ AND HUM IN FANS THAT HAVE LOOSE FAN BLADES AND ARMATURES.   REVERSE POLARITY PROTECTED, INTERNAL FUSED,   WORKS WITH SINGLE AND DUAL FANS.  CHASSIS IS 3 BY 7 INCHES,   TOP COVER IS POWDER COATED GLOSS BLACK FOR LONG LIFE.   TOP 10 MM LED SHOWS UP DURING FAN OPERATION.  EASY MOUNT ON A FLAT SURFACE.   THE FILTER HAS TWO 10-32 BRASS STUDS THAT CONNECT ACROSS YOUR FAN OR FANS.  ONE YEAR WARRANTY.