Nothing less than 7 inches.

Oh, I can never get enough. Which, incidentally, is what your sister said when--

As for this," Magnus said sliding the stele into Jace's jeans pocket, "keep it in your pants, Shadowhunter." - 219

Speed Reader: Nothing more than… "Getting knowledge in a fast way".

(Note: What's that?)

The rat, huddled in the hollow of her palms, squeaked glumly. Delighted, she hugged him to her chest. "Oh poor baby," she crooned, almost as if he really were a pet. "Poor Simon, it'll be fine, I promise-"
"I wouldn't feel too sorry for him," Jace said. "That's probably the closest he's ever gotten to second base."
"Shut up!" Clary glared at Jace furiously, but she did loosen her grip on the rat.

Looking at him now-even if she hadn't been in love with him, that part of her that was her mother's daugher, that loved every beautiful thing for its beauty alone, would still have wanted him.