The key that opens the way to the Crystal Tower.
The Sycrus Key (シルクスの鍵, Shirukusu no Kagi?, lit. Sylks Key), also known as SylxKey, is a key item in Final Fantasy III, which is required to open the way to Crystal Tower. It can be obtained by defeating Doga and Unei at Doga's Grotto.
Retrieved from "http://finalfantasy.wikia.com/wiki/Sycrus_Key?oldid=2906521"