A Revealer is a magical device that renders invisible ink visible. It looks like an ordinary Muggle eraser, though it is bright red. Hermione Granger owns one that she bought at a shop in Diagon Alley. She once tried to use it on Tom Riddle's old school diary, unsuccessfully, in 1992.[1]
Appearances
- Harry Potter and the Chamber of Secrets (First appearance)
- J. K. Rowling's Official Site