Oral B UltraThin Gentle Gum Care toothbrush is Extra Soft with 20X thinner and flexible bristle tips.^ It has a small 25mm head that cleans your molar area and UltraThin bristles with 0.01mm tips that reaches up to two times deeper between your teeth. ^vs. regular, flat trim bristles. Based on laboratory testing. Features and Benefits -with 20X thinner bristle tips^ -<0.01mm tips: Designed for deep clean Ultra Slim Tip: -2x more flexible bristle tips^ 25mm small head: -Effectively cleans molar area -UltraThin bristles reach up to 2x deeper between teeth^ vs. regular, flat trim bristles. Based on laboratory testing.