Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Warning: Not the normal size brush

I wanted to warn people these brush heads are not the normal size. I know it says "compact head" but it's hard to tell from the picture how small it really is. The brush section is just 1/4" x 1/2", 5 little rows of bristles. I find it time consuming and uncomfortable to use. I also find it noisy with a lot of vibration. Maybe these were made for children, I don't know, but it was disappointing.I had bought a newer Sonicare model and gave it away because the brush heads on the newer models feel too small to me. This brush head is much smaller than those are.I don't fault the company selling them, they shipped quickly and the item was in good condition. I just can't believe I spent almost $50 for something so useless, I just want to throw it out.