Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: very good for portable devices

sennheiser px200 is a good pair of headphones for those who would use them for a portable device. Small, compact, comfortable, they also sound very good compared to what you can get from this size of headphones. The sound is crystal clear and very good for acoustic music. With other types of music you will find them a bit sharp. But if you have adjustable EQ then they are fine. Good bass too. Only a few flaws: do not isolate you from the outside noise 100%; give a weak static noise when used with PC or something more powerful. I use them with my iRiver cd player and they are just the perfect match for it.