great hop up unit, but does not fit in ICS M4! this hop up is very easy to put together. no worry about small gears like other hop ups. you can adjust the hop from the ejector port (just like an ICS stock hop up unit). will need work done if you have an ICS M4; use a dremmel to shave off the front of the BB well. you need to round it off and make it look as close as possible to the ICS stock hop up.
VERY EASY to put together
bucking is good enough
easy to use and access hop up
for ICS M4s: better have patience to dremmel a lot of metal!
brass ring is somewhat loose, but no problems when in the rifle
Rating: [4 of 5 Stars!]