PowerPort® Bass Venting You’ll experience space-filling sound in any outdoor area, porch, sunroom, or deck. Polk’s patented water-resistant PowerPort® efficiently adds 3dB of big, realistic, musical bass output. And when combined with its anodized aluminum tweeter domes, this speaker not only delivers powerful, high-quality sound output, but excellent midrange clarity. Patented Dynamic Balance® Whether you’re lounging in your favorite chair, hosting a BBQ, or spending time with the family outdoors, you won’t miss a single word of your favorite tunes. The Atrium Series outdoor speakers deliver crisp, powerful vocals—without distortion. Their Patented Dynamic Balance® and Klippel Optimization Technologies ensure optimal material performance, eliminating driver and tweeter “artifacts” for more realistic sound reproduction at high and low volume levels. Polk All-Weather Certified Made to withstand the elements, these speakers are built to last and produce rich, lifelike, space-filling sound—no matter the weather. Atrium Series speakers exceed baseline industrial and military specifications for environmental endurance (ASTM D5894-UV Salt Fog, Mil Standard 810 Immersion, Mil-Std 883 Method 1009.8 for salt and corrosion). Speed-Lock™ Mounting System Sprucing up the patio or backyard is a cinch with easy, secure one-handed installations even in difficult locations. The Speed-Lock Mounting System ensures easy, safe one-handed installations and no-slip setting of the speaker angle. This greatly simplified mounting procedure means fewer parts and a quicker setup. Specifications Driver Complement 6 1/2″ (165mm) Dual Voice Coil Dynamic Balance aerated polypropylene cone, rubber surround, Two 1″ (25mm) anodized aluminum dome tweeter w/ rubber surround and neodymium motor structure Frequency Response 45Hz-27kHz Recommended Power 10-125W x 2 Continuous Impedance Compatible w/ 8 Ohm outputs Efficiency (dB 1w/1m) 91db Available Finishes Black & White Environmental Standards ASTM D5894-UV Salt Fog, Mil Standard 810 Immersion, Mil-Std 883 Method 1009.8 for salt and corrosion & Polk Audio Certification Cabinet material Mineral filled polypropylene Grille & Bracket material powder coated aluminum Hardware Brass or stainless steel Terminals Gold plated 5-way binding posts Mounting Options 180° Speed-Lock mounting Dimensions (w/ bracket & knobs) 12 7/8″ H x 8 1/2″ W x 9 3/16″ D (32.7cm H x 21.6cm W x 23.3cm D) Product Weight 4.4kg (each) Shipping Weight 6.1kg (each) Package Contents: Polk Audio Outdoor Speaker Atrium 8SDI, Black, 1Pc; Mounting bracket; Manual.