Wristwatch Shield

The Wristwatch Shield is a gift given to Percy from his Cyclops half-brother, Tyson. In the Lightning Thief movie, the shield was given by Luke, and the Lightning bolt was hidden in the shield's armgrip instead of Ares' Backpack.

Description
It is a shield that is magically encased within a watch. When the button on the side of the watch is pressed the full shield spirals outward, resembling a camera shutter. When expanded, the strap of the wristwatch becomes a leather brace that wraps around Percy's forearm. The shield is approximately four feet wide and polished bronze. The inside of the shield is coated in a soft leather. It has a series of engravings on it depicting the events that took place during the The Sea of Monsters. The pictures include Annabeth slaying a Laistrygonian dodgeball player, Percy fighting the bronze bulls on Half-Blood Hill, Tyson riding Rainbow toward the Princess Andromeda, the CSS Birmingham blasting its cannons at Charybdis, and Tyson battling the Hydra, as he held aloft a box of Monster Donuts.

The Sea of Monsters
At the begginning of the Chariot Race, Tyson gives Percy a wristwatch and tells him to press the stopwatch button when he needs it. When the Hephaestus Chariot attacks Percy, he pressed the button and the shield opens up to defend Percy and Annabeth.

The Titan's Curse
Percy brings it out to defend himself from Dr. Thorn, who's tail managed to create a huge dent in it. Percy later contacts Tyson to tell him that it was damaged, and Tyson offers to mend it for him.

The Battle of the Labyrinth
When Percy enters the Poseidon Cabin, Tyson is already there and presents it back to him along with a herd of mini bronze hippocampi on the ceiling. It was unfortunately lost in the Labyrinth when Percy hurls it at a Kampê, to allow Tyson to escape.