Due to new air transportation regulations. We are required to indicate that your package contains a Lithium-ion battery for safe transportation and handling. This can cause irregular tracking updates and delays while in transit, and this method is not guaranteed to arrive by the estimated date shown during check out. We apologize for the inconvenience if your order is affected by delays. Items can still ship USPS Priority Mail or UPS Air options. And should arrive most of the time in the estimated time frame. Or if using UPS Next Day, 2nd Day or 3rd Day in that time frame unless something happens to the package along the way that gets it flagged. UPS Air options will not have guaranteed deliver times for this reason