In most cases, this is because items in your order were shipped from different warehouses and there is a difference in the time-in-transit. So likely the remainder of your order is on the way.
In a rare number of situations, an item you purchased may be back-ordered. Normally, the entire order is held for shipment until all items are available, but we do make manual exceptions to this for various reasons. Also, if one of the items is special order it will be processed and shipped separately from the rest of your order. Special order products come directly from the manufacturer and are normally shipped within four to six weeks following your order.
To find out where your item is and or when you can expect to receive it, you can retrieve status and tracking information on your order by going to:
USA: Guest Tracking
Canada: Guest Tracking
Enter your order reference (found on your order confirmation and begins with a "C" or a "U" before a set of four or five numbers) and account email for access.