Using your Ethix Goggle Strap V3 is a breeze. First, adjust the strap to fit your head size comfortably. The adjustable design allows you to find the perfect fit for any head shape. When placing your battery in the holder, the rubbery grips inside will hold it securely. Just make sure to insert the battery carefully to avoid any damage. For maintenance, keep the strap clean by wiping it with a soft, dry cloth regularly. Avoid exposing it to extreme heat or cold as this might affect the rubbery grips and the overall structure of the strap. Also, check the double - stitched side straps periodically to ensure they are in good condition. If you notice any signs of wear, contact our support team.