Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not satisfied

Purchased a Hitachi NV45AB2 from Amazon. Used two different compressors (4 gal 1 hp CH extreme and a 20 gal Sanborn 5 hp) at various pressures up to 115 psi. But had to hand set about every third nail while applying Corning 40 year shingles. Returned the nailer to Amazon for a second Hitachi NV45AB2 nailer but still had the same problem. Lent the nailer to my son who uses a third brand of compressor (dual tank but don't know the brand). He reported the same problems applying composite siding but said it seem to get better with use. First Hitachi I bought based upon my son's experience with other Hitachi products and its reputation. Don't think I'd purchase another one.