Bomb Cooler is a booster in Candy Crush Saga. It adds 5 extra moves to all visible candy bombs to delay their explosion. For example, if a candy bomb has 4 moves before exploding, it will add another 5 moves, increasing the number of moves to 9. There are two variations:
The stockable variation is first introduced in level 97 of Facebook version. It can only be used in levels that start off with candy bombs already on the board.
On all versions, it also shows up if the game is going to fail with a candy bomb having a counter of 5 or below, including other losing situations like out of moves and Odus fell down. In this case, you can only buy it with gold and cannot use stocked charges.
When a bomb is about to explode, the player is prompted with the option to purchase a bomb cooler booster to play on. However, the bomb cooler only shows up in your list of items on a level that starts with candy bombs on the board. Most levels that contain bombs in candy cannons do not start with bombs visible, meaning that you can only use the bomb cooler by purchasing it on those levels. This can be problematic on some levels, such as pre-nerfed level 275 or on a level with candy bombs with a low move limit.
This booster is not immediately available on levels where there's no visible candy bombs on screen when you start the levels and when bombs can only appear in candy cannons.