https://supremesounds.com/collections/subwoofers/products/sundown-audio-sa-12 Xmax = 19mm one-way by 70% BL RMS Power = 1000-watts Vented magnetic gap Optimized high-velocity pole vent Innovative high-velocity vented frame spacer ring Black Aluminum 2.75” voice coil former for superior heat dissipation High Temperature copper voice coil wire Large aluminum faraday ring (Magnet ID) Spring Loaded Terminals Stitched-On Double “XL” Tinsel Leads to prevent fatigue and failure High strength cast aluminum frame Optimized for small ported, sealed, & band-pass enclosures List of upgrades compared to the v1 SA series (Rev.1,2,3): Magnet outer diameter increased from 180mm to 190mm Magnet slugs increased from 25mm to 27mm in height (total 4mm more height) Motor structure fully bolted together with 3x M6 bolts (eliminates the possibility of motor shifting) Top-Plate “Slits” implemented as with the X and Z series. Increased cooling & reduced distortion. Improved gap venting — more / flared gap vents. Improve pole-vent design — smoothly flared on both sides. Coil increased from 63.5mm (2.5″) to 70mm (2.75″) in diameter. Higher thermal capacity. New “U series” style cast-aluminum frame for taller cones (more x-mech both top-side from cone to spider and bottom from spider to top plate) Aluminum cast gasket to bolt-on surround. Aluminum cast vent ring to enhance thermal transfer from motor to the frame. Standard with double “XL” leads and “bolted-on” spider Larger and thicker surround (same tooling as U series). Strongest paper cones we have ever produced… new two-piece mold technique. “Large Flange” dust cap just like our larger woofers. Essentially eliminates dust-cap glue failure. Larger spider diameter on the 12/15″ models (the 10″ retains the same 188mm spider)… 12″ up to ~200mm and 15″ up to ~210mm Improved spider material for longer life.