Context I purchased a used pair of Audeze LCDi3 a few months ago, from a seller who repeated a common complaint about these headphones - they just didn't seem to fit his ears. I bought these in particular because I wanted high-quality, open-back IEMs. I wanted the open-back ones because I use these around the house and while working out, but wanted full situational awareness when doing so, I really don't like losing one of my primary senses. However, when I received them, I found that no matter what I did, or what ear cushions I used, they just didn't feel quite right. I needed both ear cushions and ear-hooks to make them work, and that was finicky, they still tended to fall out. So I decided - rather than spend hundreds of dollars on custom IEM cushions, I'd just make my own. Process The process is very simple. You have two containers, each with one half of the putty. You divide each into two parts, and use one part of each to make one ear cushion, making one cushion first, letting it cure, then making the second. You knead it together for about 90 seconds, then begin forming. It is very pliable at first, and it may even help to let it cure for a minute or two to make it easier to work with, but I was able to form it right after mixing. It sticks in the ear on its own, and I had a little extra left over from each ear, a ball about 4mm across. I allowed for a cure time, in the ear, of 20 minutes, and you can tell its about ready because the extra ball sets up nice and firm, and you can sort of feel the ear cushion "pull away" from the skin of the ear when it is setting up. When it stops doing so, you know its ready. I purchased a total of four sets of Radians, in the peach/flesh tone, to ensure I had plenty of extras to experiment with. The first set I just molded to my ears to make sure I liked the feel of them. They are comfortable, a bit harder when cured than most custom earplugs. Not a big issue, but don't pack it into your ear ridges -too- much or it will be uncomfortable when cured. The second pair I perfected the fit - I filled not only the ear canal, but also the ridge above it, and some of the ridge "forward" of it (closer to the front of the body). I then tried to cut a cylindrical hole for the IEM stem using a 1/4" drill bit (same diameter as the stem), and this worked, but the resulting earbud wasn't very tight and the ear cushion looked pretty rough around the hole. For the third set, I filled some 1/4" heat shrink tubing with epoxy, then formed the earplug around that, ensuring I had a nice, clear shot to the ear canal and the hole was level and aligned. This worked very well, and I am still using the third set today. Review They are quite comfortable. I was worried they'd be hot, or awkward, or unpleasant due to their hardness, but they stay in place very well. They are easy to put in and remove, with a little technique. I can wear them for hours without their bothering me. I can exercise, even doing lifts, sit-ups, push-ups, and pull-ups - without them giving me trouble. Even though they are supporting both the LCDi3 and their bluetooth cable, and thus not an insignificant weight of materials, they are as comfortable as when I was just using them as earplugs. That said, I cannot comment on their ability to block noise, as I do not use them for that purpose. Also, my first two attempts produced ear cushions that were uncomfortable because I didn't include enough of the forward ear ridge to help support them, and I packed it in a bit too tight. So if they do ache or put pressure on your ear for more than an initial couple hour acclimation period, you might want to try again. My only real complaint is that they aren't offered in black. All in all, would recommend for use as custom ear cushions.