The anodized blue dust cap on the Power Acoustik MOFO-152X subwoofer looks cool, and also serves a specific purpose. Because the dust cap is coupled to an aluminum voice coil former, it acts as a heatsink, extracting heat away from the voice coil, keeping it cool. ~Non-Pressed Pulp Cone~The Power Acoustik MOFO-152X is made with a beefy non-pressed pulp paper cone, ask any sound quality enthusiast what woofer cone material they prefer, and they will all say PAPER. The aluminum dust cap fits into recesses of the cone for additional bracing. ~Re-cone Kit Available~For those of you who live extreme and push a MOFO beyond its limits, a pre-assembeled re-cone kit is available. Due the the precise nature of reconing subwoofers, we recommend re-coning performed by an exeperienced car audio professional.