Fender has just released their own series of hand-assembled in-ear monitors, specifically designed for musicians and audiophiles. There are 5 models available with prices ranging from $99 to $499. These monitors provide a full frequency, flat range response (FRFR), so they will work best on stage as a replacement for traditional monitor speakers.
In ears are particularly great for cleaning up your on stage equipment and clutter. For example, they will be a great investment if you are using amp modulation because they will provide you with an extremely accurate reference of your guitar sound. In this case, there’s no need to transport a heavy guitar amp as all you need is an effects unit.
Fender was able to create a universal fitting mold by scanning thousands of human ears using 3D printed digital hybrid technology. Fender says their in-ears feel like custom molded monitors, with cushion-like comfort. They also provide noise-reduction of up to 18db, specifically for ear protection and eliminating ambient distractions.
These monitors claim to fit 95% of ears. The best idea is to pay your local music store a visit and test them out. You may also want to A/B them with other popular brands like Shure in order to ensure they are for you.
More information: http://www.fender.com/in-ear-monitor-series/