Previous upgrade???

[quartz maple]

Hi everyone, i'm so confused on what previous upgrade I need for the sprinkler attatment it shows the sprinkler I which i have in my inventory and I also got sprinkler II and all the ingreidants for it, but it keeps saying need previous upgrade. Is there something i'm missing here?

[hot spear]

That’s the final sprinkler attachment upgrade, gotta start at beginning / front of its Lineup (leftmost attachment) & research your way up from there