With add on things you simply increase your pledge by that amount, drop me a message that you did and what size(s) you need. I'll make a note on the back end that you want to add a shirt. Then when the rewards are ready to ship I'll send out a survey confirming your address and any add ons you may have pledged for. Generally, some of our stretch goals allow higher tier items to be opened up for all levels when certain social or financial benchmarks are met. Thank you for backing the project!