(4) Rockville RM64PRO 6.5" 4-Ohm SPL Competition Grade Midrange Car Speakers Totaling 800 Watt Peak/400 Watt RMS with 1.5" High Temperature Voice Coil and a Huge 90 Oz Magnet Structure 6.5 Open Basket Midrange Speaker. Power Rating: Peak: 200 Watts/RMS: 100 Watts, CEA Compliant Power Ratings. Kevlar Reinforced Black Pulp Cone, Treated Cloth Accordion Suspension, Linear Progressive Conex Spider. Kevlar Reinforced Pulp Paper Dustcap, High Tensile Expanded Steel Basket Oversize 1.5 High Temperature CCAR Voice Coil. 90oz. Magnet Structure Weight, Impedance: 4-Ohm. Mounting Depth: 3.07, Frequency Response: 85Hz - 7 KHz, Sensitivity: 103dB @ 1w / 1m. Cutout diameter: 5.79". Mounting diameter: 6.16". Mounting hole diameter: 4 holes- 0.217" x 0.276" The speakers have large 90 oz. magnet motor structures with oversized 1.5 high temperature CCAR voice coils. The expanded high tinsel steel basket dampen vibration so that all you hear is crystal clear musical response without any external motor or vibration noises. Unlike other brands, which produce their speakers by machine, the RM Pro Series speakers are hand made individually by technical teams dedicated to perfection and are subject to rigorous quality control standards. Keeping within the industry standard, these speakers are CEA compliant, which means they are tested and rated the same way that other premium brands such as Kicker, Rockford, and JBL rate their speakers. So you can feel confidant when comparing these with other midranges on the market or when matching these up with a high quality amplifier. This ensures Rockville products arent the subject of bogus claims or inflated specs.