They are adjustable, but thats the length around your head, it still squeezes in a bit. Although they are cute - they feel like they are always falling off and Im gripping my toes to hold them on. Once you pair with the machine, when you want to connect again simply turn on the headphones; it just connects and that is that simple - in case if you are not very knowledgeable about Bluetooth technology. Trademark is fake and doesn’t match to the real ones I own. Soy el size 8 pedí el mismo 8 y me quedó perfecta . One of the bolts that holds the base stabilizer to the leg was defective. Simple to put together and is extremely sturdy. com and recognize my headphones by Downloading a program by the official website so I can update it to the lates version not sure if thats a way to make sure their authentic overall good headphones Mi recomendación final es que si los vas a usar exclusivamente para el gimnasio te compres unos mas baratos, con mas batería y con mayor agarre en tu oreja por que sinceramente cuando estas entrenando (en serio) la calidad de sonido es lo ultimo en lo que te vas a fijar lo digo por experiencia. The Tracking:The step tracking seems way more accurate than my LETSFIT watch.