SD-2 10 D4 Rev 2 - Sundown Audio 10" Dual 4-Ohm SD-2 Series Chrome Subwoofer 500 Watt RMS Power Handling Strong Adhesives and Materials Mount Sub directly against the enclosure wall, eliminating the need for venting space effectively vent the voice coil through 16 holes drilled around the basket perimeter as well as a vented voice coil former allowing it to handle it's rated 500 Shallower Mount Subwoofer