Movables are objects that appear in some levels in Robbery Bob 2: Double Trouble. There are different types of movables (i.e crates, trolleys). Bob (anywhere) and NPCs (only their respective directions) can push them. Movables can be used for holding buttons as long as it stays there (unless the player pushes it away from the buttons), allowing Bob to get access to another room, activating conveyor belts, hide from NPCs if the movable has an orange hide button and/or blocking the way of NPCs. However, movables can block the player from opening a door and some of them is shorter than Bob, which means they will still be spotted by an NPC. Some movables have a limit of where the player can push.
Aforementioned, use the movables wisely for your advantage (holding buttons, blocking NPCs and the like). Some levels just need a single movable for several puzzles. Bob can push movables faster if the player holds the run button, especially if the levels have a strict time limit, although wise usage of running is still highly recommended. Take note that some movables are bad hiding places, as the NPCs will still technically spot Bob because Bob himself is slightly taller than the movables.