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Official Description

Black Metallic skin for Poweramp
Black colored dark skin with metallic buttons and knobs.

How to apply:
After installation, click "Poweramp Black Metallic" app icon, then click "Set skin: Black Metallic" (happens the first time the skin may not work, then try to repeat the application of skin again) or switch skin in Poweramp settings: In Poweramp Settings —> Look and Feel —> Skin. Then choose Black Metallic Skin.

poweramp skin com.maxmpz.audioplayer.skin