Spinner

The Spinner is a gear-shaped spinning-top item found in Twilight Princess's fourth dungeon, the Arbiter's Grounds. It is an ancient item created long ago. Link rides the spinner much like a skateboard, except he can only ride on it for a few seconds until the spinner loses its momentum. The device can also be attached to railings located on specific walls and allow Link to travel along the railing. It is essential for fully navigating the Arbiter's Grounds as it allows Link to drift across sand without sinking. The spinner is obtained after beating the mini-boss of the dungeon, Death Sword. The spinner also features a spin attack that Link can initiate to hurt nearby enemies.

The Spinner is the main item needed for defeating the boss in the Arbiter's Grounds, Stallord. It is also the principal item used to unlock the Mirror of Twilight from within the Mirror Chamber after Arbiter's Grounds. After the leaving the Arbiter's Grounds, the spinner is rarely required, with the exception of the City in the Sky. Here Link finds some more mechanisms which must be operated using the Spinner, and it can also be used to safely move over the blue tiles which otherwise fall away soon after being stepped upon.

Image taken from Zelda Elements

Trivia

 * If Link uses the Spinner before falling or jumping off a high cliff he'll be slowed down considerably and take no damage upon landing.