Ear tips for universal IEMs have always been a sore spot for me. Sure, there are sound differences between different kinds of tips, but none of that matters if the darn things won't stay in place and well-sealed because the biggest sound difference of all is **no bass at all** because the tip can't keep seal! AZLA XELASTEC tips seem like they just changed the game for me in the stay-sealed department, thus this short mini-review. My music IEMs are a pair of JVC FD01's with the stock cables, and I use a pair of Shure SE215-CL's for voice monitoring during livestreamed talks. The FD01s are heavy and put a bit of extra strain on the seal-keeping ability of tips, as we all know. Over the years I've tried a fair number of different tips: Comply, Spiral Dot, Mee, Spinfit, Symbio, and the stock silicone tips that come with the SE215s. My skin is on the oily end of the spectrum, but even after cleaning out my ear canals with an alcohol swab, I have problems with most tips breaking seal. The Complys want to creep backwards out of the canal (and are a hassle to install in the first place), and Spiral Dots keep seal for a while and then start breaking seal every few minutes. Same with Symbios, and those 3 are the only ones that are comfortable enough for me to wear for extended periods of time. I ordered a variety pack of AZLA SednaEarfit XELASTEC tips from Amazon to try them out. I had heard from someone here that they run large, and you might need to go a half-size smaller with the XELASTEC tips. That turned out to be correct. I'm a M with Spiral Dots and a MS with the XELASTEC tips. The packaging they come in is fine. Cardboard box you have to rip to get open, and un-welded hard plastic clamshell that contains the tips and -- since it's un-welded -- is very easy to open up. Compared to the Spin Fits, the XELASTEC tips seem to have a slightly smaller diameter barrel, making them require a bit more futzing to fit onto the FD01 nozzles. The part of the XELASTEC tips that mount to the IEM nozzle seems to be a somewhat stiffer plastic than the Spiral Dots, and combined with the somewhat smaller diameter of this part of the tip makes for a slightly more difficult task of mounting them. Not a big deal though. The XELASTEC material feels unlike any other IEM tip material I've felt before. Visually, it looks like the cheap vinyl tubing they sell in the plumbing section of most hardware stores, except the XELASTEC is a bit more "smoky" looking rather than totally transparent. To the touch, it feels slightly tacky, kind of like the adhesive part of a post-it note. So I guess it feels like a cross between cheap vinyl tubing and a post-it note. Getting them in the ear feels almost identical to Spiral Dots or any other comparable silicon tip, but the tackieness of the XELASTEC requires a tiny bit more pushing in. It's not hard at all to do; just different. I suppose it feels more like pushing a fully expanded Comply tip in than sliding in a close-fitting Spiral Dot tip. Initial feel once they're in feels good to me. They don't get itchy the way foamies can (for me at least) and they don't feel like a novelty torture device the way that flanged tips feel (to me). They feel invisible the way Spiral Dots feel to me. (Why do I feel like I'm writing copy for a condom ad?) Once they've been in for a few minutes, the magic sets in. They feel like they've been glued in place, except they still feel super comfortable. Earlier today I went out for some errands and tried to get them to break seal and they wouldn't. I tried moving my head around a lot, chewing, singing, and all the stuff that usually causes Spiral Dots to break seal. No luck. They stayed in like they were glued or -- as one Amazon reviewer said -- like they were vacuum-sealed in place. Again, with pretty much perfect comfort the whole time. The sound? Again, if you consider breaking the seal every 5m a deal-breaker flaw in sound (as I do), then they sound better than any other IEM tip I've ever tried! But seriously, they are a bit brighter than the Spiral Dots. I think they have a shorter barrel which puts the driver closer to the ear for me, and I think that brightens the sound a touch. I'm 46 years old and probably getting deafer by the year, so it's fine, or I can use EQ to compensate. When you remove them from your ear, they hang on harder than the Spiral Dots do. You feel the tackiness gripping your skin a bit more as you remove them. It's not uncomfortable, and psychologically, it's a nice "fuck yeah!" moment because of the years of pent up frustration I feel at tips that can't grip as well. With the tackiness comes a bit of disgustingness. They pick up bits of detritus -- flakes of dead skin, etc. -- from the ear in a way that the Spiral Dots don't. Take the good with the bad, I guess. The manufacturer of the XELASTEC tips has instructions for renewing the shape of the tips using hot water, and I do wonder if that'll be needed from time to time as oil and other stuff builds up and perhaps reduces the tackiness of the tip material? Time will tell, and it's too soon for me to say yet. I'm eager to find a way to fit these to my SE215s, but the 3mm nozzle on those is way too small for the XELASTECs, so I'll have to figure out some kind of adapter. If fit and maintenance of seal is a priority for you the way it is for me, and you have IEMs with a nozzel size that works with the XELASTECs, they are a strong recommend.