A WBShop.com exclusive! Pull out your Marauder's Map and explore the secret halls of Hogwarts while wearing this black Harry Potter I Solemnly Swear kids' t-shirt. This t-shirt was created by WBShop.com for the most dedicated Harry Potter fans. The shirt features the password to opening the secrets of the map on front - I solemnly swear that I am up to no good and the secret to close the map - Mischief Managed - on back. 100% cotton. Machine wash cold with like colors, only non-chlorine bleach when needed, tumble dry low, do not iron.