It also goes by the name "AR-Restor Hydraulic Recoil Buffer".
I bought one of these a week or so ago to put in a new lower build to go with my gas piston upper. Today (before the Bowl - GO STEELERS!!!) I tried the lower with both the standard H-Buffer and the Enidine, and the Enidine is simply incredible.
There is no obvious weight difference between the two and I had no issues whatsoever as far as bolt lock-back on last round, bolt release picking up the first round of 20 and 30rnd mags, etc. Everything functioned as normal.
When firing from a bipod, there is simply zero sight picture movement. I can keep the crosshair perfectly on target and fire as fast as possible with a standard trigger. I was able to dump mags in about 20-30 seconds and have every round land within a 2.5" group.
When firing while standing, there was just a slight muzzle rise, but it was much more manageable now because it just pops straight up a few mm, instead of jumping around more.
Without the Enidine on the bipod, the sight picture would jump around significantly, even with a firm grip on my ACE K-Grip which is mounted an inch in front of the mag well. I would have to pause to re-set the crosshair on the target, and there was no way to do real accurate rapid fire shooting.
Now this is probably not something you need if you have a muzzle brake, which does control muzzle rise significantly. But for those of us with Vortex flash hiders or similar, the Enidine really is quite an addition to your setup.
good to know