Instruct: Classify Amazon reviews into positive or negative sentiment
Query: good for travelers

I bought the SteriPEN before traveling to India and Nepal. Three weeks on trains and in modest lodging, using the pen to sterilize one liter of water at a time.I learned that I had to insert it deep into the water, just a little beyond the rod, otherwise it didn't work. I used it 20 - 30 times and it took away the uncertainty about the water. I'm taking it with me to Mexico this month. It's lightweight and small, so easy to include.