All of these newly designed parts allow for lower frequency reproduction. The bolted down spaced spider design keeps it all linear. The m3 8 uses a gap cooled design to allow the 2" copper coil to thermally take more power than other 2" coil motors with the traditional pole venting. Mounting Hole Diameter 7.25.Outside Driver Diameter 8.5. The item "8 inch subwoofer 2 ohm (Lot Of 4)" is in sale since Saturday, October 9, 2021. This item is in the category "Consumer Electronics\Vehicle Electronics & GPS\Car Audio\Car Subwoofers". The seller is "weaver_robert_1981" and is located in Harker Heights, Texas. This item can be shipped to United States.