How to use the astrological stone of tower defense elves

Exchange voucher. According to the information of the mobile game network, the astrological stone of the tower defense elf is a redemption voucher in the "Star Tower", which can be used to challenge the fourth floor. After use, it can change the position of the defensive star that is already in the battle, enhance the probability bonus of winning the prize and repeatedly recruiting the same-star elves, and make the battle more strategic.