Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Do NOT buy these batteries

I have purchased non-Canon batteries in the past and they've worked well. Not so with these. From day one, they have not held a charge. Incredibly, I noticed as I was packing for a trip that they weigh a fraction of what the Canon batteries weigh. You can squeeze them and compress them with your fingers, which of course is impossible with a proper battery. Clearly they are skimping on the substrate. They will leave you angry and ripped off. They are completely useless.