the electricity used across our entire manufacturing supply chain—including material extraction, component manufacturing, and final product assembly—to 100 ...

https://www.apple.com/jp/environment/pdf/Apple_Supplier_Clean_Energy_Program_Update_2020.pdf

or vice versa (REF_HTF) to control for the variable of listening fatigue or practice effects after。

https://www.apple.com/jp/health/pdf/Hearing_Health_Features_on_AirPods_Pro_2_October_2024.pdf