Find an official MSL blood drive or blood center and schedule a donation to save lives. Vouchers are issued by the blood center with a SPECIAL THANK YOU EMAIL. You must donated at an OFFICIAL MSL Blood Drive posted on the Blood Drive Map. Make sure when you sign up for a blood drive that you give them your email address and let them know you will be waiting for your thank you email. Vouchers are good for meet and greets and other MSL VIP activities at events we participate with. In your thank you email you will have a link to download your voucher, or use the voucher on your smartphone. iPhone users can save the voucher in there iPhone Wallet.