Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Expensive, but probably the best you'll get

Firstly, if you're not planning on using this product with batteries, then you're going to get a humming sound in the background. If you use batteries, then there's no interference.The transmission power is good, as stated.This product is expensive ($USD90). I bought a similar product, of lower quality, in Hong Kong for about HKD30 (~USD4), and it did the job, except that it would occasionally just turn off if it was knocked. Power output was OK. But I wanted something that was reliable. This prodcut, so far, is.Read the other reviews. Accept the fact that you're never going to get perfect transmission. Use batteries. If you want the best FM transmitter and acknowledge that none of them are perfect, then wear the cost and get this one.