0.25 mm Firm Toothbrushes 0.30 mm Extra Firm Toothbrushes Buying Options Buying Options Customer Reviews 4.6 out of 5 stars 2,066 4.6 out of 5 stars 2,066 Price $8.99$8.99 $8.99$8.99 Bristle Diameter 0.25 mm 0.30 mm Firmness Firm Extra Firm Firm Bristles or Extra Firm Bristles Toothbrushes are classified as soft, medium, or hard based on the diameter of these bristles. The diameter ranges for these classifications are 0.18 mm and below for soft,0.18 to 0.22 mm for medium,0.22 to 0.25 mm for firm.0.25 mm and above for extra firm. Cross Bristles Designed to flex and then straighten, actively penetrating between the teeth to lift and sweep plaque away. Textured Tongue Cleaner Located on the back of the toothbrush and helps remove food debris and plaque on your tongue to leave your mouth feeling fresh. Easy-to-grip Handle Silicone Sure-Grip Handle is ergonomically designed to fit easily into your hand for a smoother brushing routine. Solve Your Stain Problems Smoke StainTartarCoffee StainTea Stain