Bitvae D2 Toothbrush Heads (Black) The dark blue bristles on the toothbrush head fade in color with use - when they have completely faded, it's time to replace it with a new one. The specially shaped bristle design fits better to the shape of your teeth, reaching into the gaps between them. These heads are intended for the Bitvae D2 toothbrush. The set includes four pieces. Note: the color of the bristles may vary. BrandBitvaeModelD2ColorBlackCompatibil ityBitvae Daily D2