March 2019 Update - the first set of these i picked up more than four years ago. i damaged those and replaced them shortly thereafter. since i've dealt with near non-stop perpetual noise from the adjacent mcmanision construction that won't end until our sun turns into a red giant. or at least that's what it feels like at our end of things. so these earbuds were a "save my sanity and get some sleep" act of desperation. these things not only saved my sanity they made doing something so mundane as watching tv with sound possible. yes it gets that bad. i still have the bose over-the-ear noise cancelling headphones but they don't even come close to cutting out the low frequency stuff these do. this last set i've used every day these past couple of years. i have had not one problem and they have out performed by highest expectations. simply put for blocking out the worst noise there is nothing better on the market today based on my own experiences.i have had bose qc15's, still do. however they aren't comfortable to wear for a long period of time and the noise cancellation for lower frequencies was not as good as i needed. that due to a seemingly perpetual construction project going on next door! from jack hammers to the low frequency noise put out by all those running diesel engines. so i tried a couple other under $100 earbuds with active noise cancellation but found none worked nearly as well as my old over-the-ear qc15's. so i begged for a pair of these for Christmas and that was back in 2016.what i found was the professional audio reviewers were right, nothing even comes close to blocking out lower frequency sound that these do. at the top end they are a little less efficient than their over the ear models, like the qc15's but not by much. as for comfort due to the way the tips are designed i can wear these for eight hours and forget i have them in. you'd think again due to the design you wouldn't get a good seal to block out noise but you do. in fact it is good enough that even with noise cancelling off they still block out as much noise as those sub hundred dollar models i tried initially.the sound quality is very good. the 'character' changes with the power off but still not bad. it does exceptionally well with bass, okay with mids and good with highs. as to the battery, even after a couple of years i have noticed no degradation. my sister has a pair she got back in 2012 and her battery is also still good too.the buds comes with three sets, different sizes of ear tips. i purchased spares at the outset but didn't need them until recently. in fact just yesterday while removing one to clean it did the silicone crack. so nearly after a couple years of near daily use and didn't need to replace a tip till as said yesterday. fyi you also get a nice zipper carrying case, usb charging cable.in the end though these earbuds sound very good i only bought them as a means to save my ears from the constant construction noise. they did the job and much better than expected. for lower frequency noise these are nothing short of miraculous in how much they block. i mentioned construction noise and diesel engines but there's more! our neighbors son just got an old harley and put straight pipes on. when he idles it you can hear it easily 1/4 mile off. not exaggerating wish i was. with these powered on i can't hear him idle it.as to quality no complaints just as i've always experienced with bose products. priced a bit on the high side but you get what you pay for.fyi bose has several models of active noise cancelling products. as i found first hand they each have their strengths and weakenesses in how and what they block out. as i mentioned here the older qc15's are better blocking top end noise but the qc20's were much better at the lower end. point being know what sounds you are most wanting to block out prior to choosing which model of active earbuds/headphones you're going to get.in conclusion the longer i have these the more i find them to be more of a necessity rather than a 'splurge.' i'd sooner give up my toothbrush than my bose earbuds, though not long term lol. those sentiments are why i recently purchased a second set to keep on hand for that day in the future when i either accidentally kill mine or they finally die from old age.these are simply the best based on other products used let alone a few thousand hours of personal use.Tip - if you really need EXTREME noise blocking put these on then put a pair of bose qc15 over-the-ear or newer model. with both active noise cancelling systems on you get the best of both worlds so to speak. by double layering in this method you can't get more isolated from noise where extreme situations warrant.*on the chart pictured the BLUE line is noise cancellation for the QC20's the other line is for the QC15 over-the-ear model. surprising to see the 20's perform a good deal better blocking low frequencies than do the older, larger QC15's. sorry no chart with anc23's.