The giveaway apparel piece size and fit selected for each event is guaranteed to each registrant up to a particular date. This is typically 7 to 10 days prior to the first day of packet pickup, but will vary based on the item.
After this deadline, size, fit and other available options will be limited to remaining inventory. If a size/fit is available to you during registration after the deadline, you will be able to select the option prior to checkout. If the size/fit is greyed out, it is no longer available.