The tower box contains a random tower with the following rates:

20.0% - Light Thrower (Common)
20.0% - Dard Launcher (Common)
20.0% - Apprentice Archers ( Common)
12.5% - Earthquaker (Rare)
12.5% - Energy Centry (Rare)
4.5% - Training Tower ( Epic)
4.5% - Darkness Pulpit ( Epic)
4.5% - Bone Launcher ( Epic)
1.5% - Time Controller (Legendary)
1.5% - Flame Thrower ( Legendary)