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These appeal to me but the non-replaceable lithium battery throws me off. I had to replace a pair of Sony ones when the battery went dead after about 15 months. So what is the life expectancy of lithium batteries ? Googling brings up a lot of 'ifs' and 'ands' and 'buts'
I just don't want to spend that sort of money on something which will become an expensive paper weight within a short period of time.