Chinese languages

Greetings~ In the beginning of October I am going on a trip to China for three weeks. I am hoping someone will be able to write something in Chinese for me, that I can print and keep in my wallet. You see, I am deathly allergic to shellfish/certain types of seafood, and am concerned about the possibility of eating something that I shouldn't.
I was hoping someone could write for me in Chinese that I am deathly allergic to shellfish (crab, lobster, crawfish, shrimp), this way I have something to show to waiters/waitresses when I eat in restaurants.
Thank you very much in advance for your help, I will look for postings!

use Big-5 code to read the chinese

對貝殼類海產敏感（包括蝦蟹）


direct translation
對　to
貝殼類 sellfish kind
sea food 海產
allergy敏感
包括 including
蝦 shrimp
蟹 crab

我对贝壳类海鲜过敏（包括虾、螃蟹），我不吃这些，谢谢。