I found an interesting article Titled "A Guide to Understanding Surge Suppresion" written by Paul DeLaup, Lightning Elimination Systems, Covington, LA. It can be found at http://www.semiconductorfabtech.com/.../ft11-4_05.pdf and is a pretty quick download consisting of minimal, but useful graphics in a 6 page document. Relatively small, in my opinion it should be saved to one's hard drive for future use. While coming from the Semiconductor side of things, nonetheless, the explanations and things to look for or be aware of are quite relevant to the audio enthusiast. To a large degree this article provides an understanding of UL 1449 which has to do with Transient Voltage Surge Suprressors. For those who are interested in reading the scope of this Underwriter Laboratory standard, it can be found at http://ulstandardsinfonet.ul.com/scopes/1449.html It is also my understanding, and if I am wrong, please someone correct me, that there is an optional part to this standard that is at a company's discretion to perform. This optional part has to do with evaluating the performance of the unit by testing for endurance and was commisioned by the Federal Governement. Basically, if I understand it correctly, there are several permutations of the optional part. So for example, if your unit has been certified as meeting UL 1499 with the provisios that it's a Grade A, Class1, Mode 1 device,it means the following: It survived 1000 surges of 6000 volts, 3000 amps There were no failures or degradation of performance The voltage that was let through did not exceed 330 volts The ground was not contaminated. That's pretty impressive and not many units can take such a battering. For those concerned with longevity, this would seem to be a mighty damned fine 'tweak'. Personally, I am unclear as to where UL 1499 falls into this whole mix. I could not find anything about it at the UL site and possibly this means its been superceded by UL 1449. Keep in mind that having a surge protector does NOT imply that it'll stop surges exceeding 120 volts. Bill Kane I believe has posted on these high quality, devices that apparently meet the most rigorous aspects of the additional, non-mandatory, devices that are UL 1449 certified. Zerosurge sells through authorized dealers (info on models, spec sheets, some pictures at www.zerosurge.com) and to find one, a toll free number is 800-996-6696. They also will sell direct. SurgeX (info, specs, pictures, etc at www.surgex.com) is another company that also meets the optional UL 1499 code and provide emi/rfi conditioning. I found their products at http://www.stereoaddict.com/manufacturer.asp?2=1119 and it seems stuff is about 10% off of list. I'm sure you can get additional sources from SurgeX at (215) 766-1240 and possibly list prices. Adcom, as Bill Kane has already pointed out, uses a non-MOV system and their surge suppressors can be found at http://www.adcom.com/main/surgesupressors.htm and they also pass the optional testing in UL 1499. There may be others and hopefully people will find out just who else and post em here.