This hop up is a good copy of that other well known aluminium hop up of the same style and, as such, has the same issues unless set up absolutely right. Not a hop up for beginners, I would suggest.
The problem with this model, and it's quite a big problem, is that there is no retaining ring holding the adjustment wheel against the hop up arm. This means that the wheel easily, and frequently, moves backwards and the hop up arm pops out of its groove, leaving you with zero hop up!
The only way to successfully get the wheel back on is to strip the barrel from your gun.... not a great option in the field.
This could be fixed by simply adding a retaining ring, as in the ProWin of the same design.
What I did was to fit a silicone washer to the back of the hop up which, when installed in the gun, pushes against the adjustment wheel and the front of the gearbox mechanism, preventing the wheel from sliding backwards.
This also has a secondary bonus of lining up the feed tube correctly with my Amoeba mid-caps, winner all round.
So to conclude, a good hop up at a reasonable price, but with a little 'Heath Robinson' needed to prevent frustration at the worst time.
Verified purchase:Yes | Condition:new | Sold by:hwairsoft