First, it is very important that you use the correct size enhancers (rubber tips). This headphone features the TwistLock technology that is uniquely designed to fit in the bowl of the ear (vs. inner ear). They may look bigger than traditional ear buds, but this design provides the most secure fit to ensure they never fall-out in the most active workouts. To properly put them on, first make sure you have the Right and Left ear bud in the correct ear. The number to indicate the enhancer size is featured on the inside of the enhancer next to the large L or R (left ear, right ear). Next, gently insert the enhancer into your ear with a forward motion towards the jaw, which should twist and lock the enhancer into place. After the enhancers are securely locked in the ear, we recommend wrapping the ear loop up and over the ear for the most comfortable fit. Please note, the ear loop should not be pushed backwards to align with arc of the ear perfectly; it is likely there will be negative space between the headphone and your ear. The size 7 will be featured on the model; two smaller sizes (5 & 6) and one larger (8) will be included in the packaging. If you experience discomfort wearing the size 7, try the next size down. If you try a smaller size and the headphones fall out easily or the enhancer does not extend fully to the back of the bowl of the ear, you should try a bigger size. If you’re unable to find a secure fit, one our fit specialists can assist you with a different size or guidance on how to properly wear these headphones. For any questions or concerns regarding fit and sizing, please contact your local JBL Customer Support or please email us from our Support page at https://www.jbl.com/support-contact.html.