>> so far I've never encountered a filter than my three legged wrench wouldn't take off, <<
Bird .... that's what I usually use too ... but I had trouble using it on .... of all things .... my L3710 .... not enough room to get it on in the right position for it to tighten properly. And you're certainly right ... you usually need to be in a position to use both hands otherwise it's frustration city!
too bad that common sense ain't