Harry sighed and waved a hand.
"All right."
"Go on, show me."
Dobby gently touched the probe to the inside of the trench coat's left breast.
The empty space immediately lit up in a pale silver ring.
"First feature."
"Environmental Threat Identification."
"It won't think for you."
"And it won't fight for you."
"It will only bring things you might otherwise overlook to your attention."
Harry frowned.
"How?"
Dobby pointed at his collar.
"Look at the window again."
Harry turned his head.
This time, before he had even thought it through,
the trench coat's lining had already warmed up.
Three short lines appeared on his left sleeve.
One red.
Two white.
Harry said quietly,
"Wind."
"Temperature."
"And someone outside."
Dobby's eyes lit up.
"Correct."
"The red line doesn't mean an enemy."
"It means a variable worth your attention."
"The white lines mean a source of change is approaching."
"If you misjudge it,"
"that's your business."
"It only provides a warning."
Harry walked to the window.
He gently lifted the curtain.
Someone walked past a window across Privet Drive.
The light cut a shadow in two.
Nothing was out of the ordinary.
But if he had been doing something else just then,
he probably wouldn't have noticed.
Still, even I can't keep watching my sleeve for changes all the time, can I? Oh, the temperature warning.
"What's the second feature?"
Dobby adjusted the dial again.
A faint tremor ran through the hem of the trench coat.
"Thermal and Magic Dual Concealment."
"The range is limited."
"It doesn't last long."
"The more complex the environment, the more it tests the user's judgment."
Harry asked,
"Meaning other people can't see me?"
Dobby immediately shook his head.
"It's not an Invisibility Cloak."
"Don't think of it as that simple."
"And don't think of it