Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Worth buying

The first model I received was defective and wouldn't even start. The seller immediately sent a new one and it works like a champ. The only reason I did not give it a 5 is the quality control issue on the first one. This is an economical answer to keeping watches that need continued winding to work ready to go when you are not wearing them. I would recommend the product