TTStyle as instance variable error

I declare TTStyle in my class and it has error :

 expected specifier-qualifier-list before 'TTStyle'

I don't know what's wrong with it.

Can any one help me?

Thanks.

You have to import the Three20Style.h header. If you have three20 set up the standard way you do this by

#import "Three20Style/Three20Style.h"

before @interface.