||This hop-up is nicer than I thought it would be.
It was pre-assembled when it arrived, and fits my m4 nicely.
Easy to install
The skinny spring on mine bent (but it was probably my fault)
The gear that you use to adjust is a bit hard to turn, but there's probably
a way to fix that.
Overall, it is a simple metal hop-up that does its job.
Rating: [5 of 5 Stars!]