Using your Vault II earphone case is easy. Simply open the case, place your earphones inside the foam interior, and close it up. The replaceable O - ring can be adjusted to fit different earphone sizes for a snug fit. When traveling, just toss the case in your bag without worry. As for maintenance, wipe the case with a dry cloth if it gets dirty. Avoid using harsh chemicals as they may damage the high - impact polymer. If you notice the O - ring is worn out, replace it to keep the case airtight and weatherproof. Keep the case away from extreme heat or cold to maintain its durability.