Etymotic ER-6i's go very deep in the ear without protruding and can offer very good isolation. The ER-6i can take all the standard eartips including the highly isolating Shure black olives and Comply foams.
You'll need to experiment to see what eartips work best for you. The ER-6i comes with a pretty good fit kit already, but I'd suggest getting a set of each size of the Shure blacks (available at Amazon and elsewhere) and a set of each size of the Comply foams (available at
EarplugStore). Many people like the Shure blacks best, but I get at least equally good isolation, and significantly better comfort, with the Complys.
You may also want to order a bottle of
Oto-Ease to help you get your tips in. If you're not accustomed to IEMs, insertion can be both tricky and uncomfortable, and a bit of lube really helps.
Depending on your ear canals you might be able to get equally good isolation with the somewhat better-sounding ER-6 (non '-i'), but as it doesn't take standard sized tips, the available tips are fewer so it's a bit less of a sure thing.
Both the ER-6i and the ER-6 can be worn "Shure-style" with the cord looped up around the ears instead of hanging down. If your helmet doesn't already hold the wires in place, you can remove the Ety's shirt clip from below the Y-junction of the wires, reattach it above the Y, and then slide it up to snug the wires in place.
