Ultimate Ears are not the only option
There is a lot of promotion of the Ultimate Ears product on here, and because hardly anyone ever suggests alternatives, it starts to look like there is no realistic alternative. I'm not dissing the Ultimate Ears product, I just want to supply a bit of balance.
I've been using Shure SE 210 in-ear headphones with my Zumo 550 with excellent results. They basically do the same thing as Ultimate Ears, but the plugs are not custom-made for the shape of your ears. You get a selection of shapes and sizes of plugs that clip onto the in-ear headphones, and you find the one that suits you best. At £65 they are less than half the price of Ultimate Ears and don't require a visit to a specialist to make a mold of the inside of your ear.
Probably the Ultimate Ears product does reduces external sounds by even more, but the Shure headphones reduce it by just as much as the Howard Leight brand disposable ear-plugs I was using before, which I believe are sold as industrial-use hearing protection. If you are used to riding with disposables, Shure headphones give you the same level of quietness. If you are NOT already using ear-plugs, prepare to be astonished by the difference - it is incredible how much noise even the quietest helmets create as wind passes over them but you only notice it when you remove it with hearing protection.
Whether you go with Ultimate Ears or Shure, the very best feature of these products in my opinion is that you actually have the music volume really low, and it sounds like you're in listening room with a decent hi-fi on a proper volume. This is nothing like the old-skool way of listening to a walkman with the volume all the way up to overcome the wind/engine/exhaust noise. You can sit in a silent room, take the plugs out of your ears and leave the music playing, and be unable to tell that they are on until you put them within an inch of your ears!
I used my Shure SE 210 plugs for a full 8 hours continuously riding a very scenic route from Cornwall to East Anglia (only 10 minutes of stopped time for fuel and I didn't take the 210s out for that). I listened to a mix of music and recordings from the radio plus my Zumo's directions, and when I took them out at the end of the day my hearing was instantly completely normal! I will concede the Ultimate Ears product would likely have been a bit more comfortable though.
Which ever way you go, I'm sure you'll be impressed. With my favourite music and radio shows playing, with perfect clarity, I find my rides are always longer than planned. I just keep looking for detours and roads I haven't tried before, safe in the knowledge that if I take a wrong turn, the Zumo will guide me back home with no fuss.
