Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Durable

I bought a Gaiam Balance Ball Chair over 6 years ago. The chair has proved very durable and maintenance free (other than needing the occasional inflating). I use it every work day for hours and hours. I find it to be at least as comfortable as your average office chair over an extended period - more comfortable than many. Also, it is fun. Put on your headphones and bounce to your favorite music while you work!To those people who say the ball is too small - try inflating it more. You will be surprised by the potential range of sizes the ball can have.