Suitable for crevice between teeth of diameter 0.8-1mm Super soft & ultra-strong wire: Resists breaking bending or being pushed out of shape.A tapering nozzle: The tapering nozzle connects between the toothbrush & the handle added wire strength & more durable.L-shaped long handle: Easy to grip & allow reach to the back teeth. The handle & the head is in right angle which is easier to clean the gap between teeths.