Tron- There is more to the Isis than a sponge b/w a couple pieces of plastic (delrin actually).
From their website:
Three systems are used to control the recoil effect: - a) the hydraulic shock absorber that does the bulk of the work. b) The mechanical resistance of specially manufactured springs which can be varied in strength, dependent on each individual shooter and c) The pneumatic smoothing effect created by metered air release as the unit compresses. These three mechanisms working together create a linear deceleration of the gun over a very short distance (about ¼”) which is hardly noticeable to the majority of shooters.
From my research, they seem to be far and away the lightest recoil unit one can install, so if the balance of your gun is a major concern, they may be your only option. They may not necessarily be the best/cheapest option, but possibly the only option if you don't want to chance the weight/balance of your gun significantly.
I installed a couple of dozen Isis units for a Texas gun dealer some time ago. I am not impressed! I have also removed at least that many and replaced them with both RAD's (when I was doing them) and my own Bump-Buster's. I agree with Tron; the Isis, imo, is a spendy piece of junk. The British agree.....some of the ones I've replaced have been for U.K. shooters when they come here to compete. I am in negotiations as we speak with a large firm in England for them to become the U.K. distributor for the Bump-Buster because they want a better system than their British built Isis. They tell me that many of their Junior shooters shoot in excess of 60,000 targets per year and need better recoil reduction than the Isis gives them. Yes, they said 60,000!!!!!!!
I do not understand why you would bash someone elses product.
There is a positive and negative to any of the many recoil devices we have at our desposal,none of which are trouble free.
I have an Isis on one of my Kolar Sporting guns and have never had any issues,it is a good functioning unit and all of the components except the delrin housing have (Made In The USA) stamped on them.
If I should need to replace the cylinder or bearing parts,they are available in Dallas Texas 50 miles from me.
I also have a BumpBuster and A RAD on my other two Kolars and a Gracoil and a Counter-Coil on two of my 680 Berettas.
I have had issues with the RAD and the BumpBuster and the Counter-Coil altho be it minor ones,like the adjustments loosening during a tournament,a hydraulic cylinder leaking oil in my stock from the Counter-Coil,but what the heck,I just carry plenty of tools with me to keep them going.
I have till yet to ever have any issues with the Isis and do not think they are junk!!!!!!!