Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Bulky lock, terrible mounting system

The lock itself seems fine, but considerably heavier than I anticipated. The biggest problem is the EZ-Lock mounting system, which is atrociously bad. I tried to get it to stay on my bike for upwards of 4 hours with no success. The instructions have grainy, thumbnail sized black and white pictures and terrible, hard to follow writing. They refer to a youtube video guide which appears to have been taken down. If you intend to mount this lock, please get a different one.