The award winning MB Quart nautic premium waterproof marine certified, 6. 5 inch coaxial speaker for boat, RV and off-road vehicle audio installations. Sold in pairs with 3 color grill options included in each box. The premium line offers high Tech waterproof protection to assure years of great music and protection from the elements along with the ability to Personalize the color of the speaker with 3 different inserts. Speaker impedance (4), mounting Diameter/Cut out (5. 6 inches), Mounting depth (3. 05 inches).