Im also typically walking on uneven ground and up and down steep hills. 3360 variant sensor, 50m omron switches, RGB and a safe shape. I don?t use Apple Watch so cannot comment. One of the sides of the earphone is purposely shorter then the other. I picked the XL, which fits size 11-12, per the ordering info, since the Large showed a fit of up to size 10. They are cheaply made and falls apart after wearing them twice. So good luck. These fit me perfectly. Way more than a well positioned sm57 for example. The bag came exactly as shown and is much more compact than I expected (and it easily folds up and fits back into the storage bag!