Purple boosters are defense boosters (placed in friendly cities), red boosters are attack boosters (placed in enemy cities). Do not place the boosters without knowing what they are for.
Why?
If you put a booster without knowing it, you can ruin a war in your club.
How should it be done?
Your club is a great ally, ask what each one is for if you have doubts. A brief summary:
DEFENSE BOOSTERS | |
The pump or accelerator recovers energy faster. | |
The dud serves to divide the points in the city you put on. | |
The umbrella serves to protect you from general attacks. | |
ATTACK BOOSTERS | |
The jackpot serves to double the points in the city that is placed. | |
The vampire slows down the energy that is recovered. | |
The freeze prevents the city from attacking. | |
The thief booster steals energy from the city to which it is attached. |