Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Performance is good but ...

Exceptional performance as Weller is known for, but for some odd reason; it unscrews itself - which is can be dangerous for the sensitive component board or for anything for that matter. I found that rubbing the end with a bar of soap (the screw on end) before screwing the tip on (the one you are going to use) has eliminated this loosening of the screw tips.