Instruct: Classify the given Amazon review into its appropriate rating category
Query: Seal can be unreliable, especially when sweating.

I got this as a replacement for the same one, which I loved and trusted, but perhaps they’ve changed something or my face/head has changed; I don’t know. The fit/security isn’t consistent. I don’t really trust that I’m getting constant protection, especially if I start sweating or am moving a lot. It can start to slide and dig into the bridge of my nose, which really hurts and leaves a mark. I verify fit using positive and negative pressure tests before using. It can sometimes be very difficult to establish proper fit/protection, and I’m not sure why. I have to constantly try many adjustments and even tried other sizes and models. Sometimes while working, I notice odors, so I don’t trust the protection. I guess I’m still searching for the perfect respirator...