This thing is great. It is pretty easy to install into a KWA hopup chamber since it's so slim and the KWA chamber is so tight. It gave me good groupings when I had it in my gun. I went to switch it to a new gun, and I accidentally ripped it. I probably didn't put any silicone lube on the outside of the inner barrel while putting it on so it wouldn't slide on/off so easily.... that's what probably led to the ripping.
When it was in my gun it was awesome.
It's cheaper than a firefly, and it gives great groupings. It's probably the cheapest upgrade (and simplest) to get better accuracy.
Good bucking made just for the awkward KWA hopup unit
Relatively cheap (even though it's a stupid piece of rubber)
Can rip if you're not careful
Rating: [5 of 5 Stars!]