Aside from sometimes offering ambient mics for hearing your surroundings, exercise-focused headphones and earphones typically offer water-resistant builds and extra accessories for a secure fit. The most important feature of any exercise-focused headphones remains the IP rating. IP stands for ingress protection, and you often see ratings such as IPX7 or IP65. The first number represents protection against solids like dust (X acts as a placeholder, usually because the manufacturer didn't officially test against dust or solids), while the second number describes protection against fluids like water and sweat. For more, see our guide to IP ratings. As mentioned, another consideration is in-ear fit. We all have different ears, and some earphones fit better than others. If you've had trouble getting in-ears to stay in place in the past, consider a pair that comes with multiple eartips or earfins that sit against the ear to help aid stability. It's also worth considering foam eartips (which sometimes ship with earphones, but are less common than silicone) because they expand in the canal to create a stronger seal, much like earplugs. They also often have the benefit of increasing the bass response. For more, see our picks for the best true wireless earbuds for running.