The toothbrush heads crumble in your mouth.
I have used these toothbrushes for a couple years now.  But in the last couple of months when I have bought new toothbrush heads they crumble and crack.  I have had the tiny bristles all over in my mouth.  The last 4 heads have done this. I head lasted 2 weeks.  The new ones I received yesterday, I used it once and it fell apart.  I was told by the seller to contact the manufacturer, but when I go to Voom Sonic, you cannot contact them.
Rating: 1 stars