They take one of the slots in the "Weapons" tab, next to the pistol, the Molotov and fists, with an icon of a compact grey pair of binoculars. The wheel also has a separate "Items" tab, so the binoculars count as something you pick just like a weapon. That suggests they can be pulled out at any time to look into the distance, although Rockstar has not yet explained what they are used for in the game.