The foam strip themselves are about 2~3mm in height, 5mm in width and just a little over 40mm in length. The two ends are shaped with a slight angle. When applied to the custom, it is supposed to have an angle so the two ends never actually meet but rather twisted. The base of the foam is a piece of very sticky tape. So sticky in fact, you really don’t get a chance to reapply it if you did it wrong the first time as tearing it out will very likely destroy it. There is definitely a learn curve there. One more thing to note is that – you must make sure the sticky tape follows the curve of the custom mold and never try to force it to even bend slightly, or else there will be a tiny ‘bump’ forms in the tape and it will irritate the ear canal. The foam itself is pretty much the same as the foam used on Comply’s normal foam tip, which is very soft in nature. Just like any Comply foam, it doesn’t really last very long, probably only a few weeks on heavy use on each strips.
The position on where you apply the Custom Wraps is pretty crucial to get the ‘right fit’. Having the foam too close or too far from the nozzle will either make it too tight or not tight enough. I’ll say there is a chance you might not get the right position in the first trial, at least I didn’t. There are however 10 strips in each US$18 pack so you can afford to miss the first time. Lastly, and on the more obvious: Custom Wraps is designed for hard acrylic custom and not for soft silicone mold, and you shouldn’t use it when your custom mold is already pretty tight.
I used the Custom Wraps only on the right earpiece of my custom IEM as my left side is already very tight. The right side isn’t actually loose either, but I do need to make some minor adjustment every 20 to 30 minutes or so to make sure the fit is perfect, especially if it is a hot day with lot of sweat and earwax. I have the foam strip applied too far away from the nozzle at the first try but I eventually got it right the second time. It is pretty much a trial and error process. But once I had it right, it really does fit like a glove. The seal was tighten up and I don’t have to adjust it much anymore and I don’t feel any discomfort at all. The foam collapsed in such a way that I don’t feel any intrusion at all. I do however want to stress that you have to make sure the sticky tape isn’t bend or bumped up in any way to ensure maximum comfort.
All and all, the Custom Wraps performs as it should by ‘fine tuning’ the fit of a CIEM. It is definitely worth a try to CIEM user who are looking for the elusive last 5% of a perfect fit.
A thank to Comply for the preview sample.
For those in the US, you might have a chance to get some free Custom Wraps here: http://www.head-fi.org/t/736199/having-ciem-fit-issues-try-comply-foams-custom-wraps-for-free