Tube Coolers pros and cons

I would think that if the cooler is made of a material that conducts heat better than air (which isn't hard to achieve, and brass certainly does), and it fits snugly against the glass, then it should perform like an amplifier heat-sink and cool the tubes. If however, the fit is not sufficiently snug, any air pocket between the glass and the cooler will serve as a thermal layer. I'm no scientist; it's just my two cents worth.

IME they tame microphonics and extend useful tube life 25-50%. The latest design has vanes in the pleats to improve convection. Some sizes use a carbon fiber sleeve and some do not. I can't imagine not using them with pricey NOS tubes unless there are space constraints.

I want to thank everyone who has responded thus far;I think I will give them a shot;I just traded in my cary slam 100's for audio valve challenger 180's and was asking for people who had experience with these monoblocks;one of the responses recommended pearl tube coolers;so that brought forth the question on coolers.