A classic IEM that’s been refined over decades, the Etymotic ER4 gets its latest update in the ER4SR and ER4XR: two models that deliver accurate, reference-quality sound with excellent noise isolation—up to 42 dB of reduction, to be exact. Each features precision-matched and custom-tuned balanced armature drivers inside sleek anodized aluminum housings, along with a detachable 5-foot-long cable that ends in a 3.5-millimeter gold-plated stereo plug. Plus, their design completely seals the ear to block out the outside world. Improving upon the ER4S’s tonal accuracy, the ER4SR IEM is ideal for engineers, audiophiles, and discerning music lovers. If you appreciate a bit of extra presence in the lower end, opt for the extended-response ER4XR IEM. To learn more, check out this Headfonics review.