Mobile Phone Armband With Adjustable Strap & Key Pocket 1. This running armband is made of a blend of high-quality Lycra and neoprene, which is gentle on the skin, waterproof and sweat-proof, and durable. 2. There are 2 sizes for you to choose from: medium is suitable for mobile phones within 6.2 inches, and large is for mobile phones within 7 inches 3. With a smart design of double buckles and adjustable hook and loop fastener, the armband can be easily adjusted to fit your arm. 4. The built-in key pocket secret compartment can store your house keys while exercising; the built-in card pocket can store change and bank cards. 5. The 5-headphone jack design allows the earphone and charger cutouts to access the phone directly through the armband. 6. The touch is sensitive, easily answer calls, manage playlists, or activate the stopwatch without taking out your phone. 7. The mobile phone arm bag is perfect for most sports activities such as jogging, running, cycling, climbing, cross-training, hiking, mountain biking, gym, rafting, etc.