Key of J-Stl

The Key of J-Stl (also known as Sky Temple Key 1) is the first Sky Temple Key required for access to the Sky Temple in Metroid Prime 2: Echoes. Returning to the Battleground in Dark Agon Wastes, Samus must climb the ledges on the left and locate four floating platforms with the Dark Visor. Ascending them, Samus must locate a ledge with a Flying Ing Cache using the Dark Visor and Screw Attack to it, then destroy it to get the Key.

Dark Agon Temple Key 3 is also located in the Battleground.