Stroker 21" Folded Horn w/ 4" Voice Coil & extreme low end bass! - Unprecedented 21" Woofer using Stroker Technology for increased power handling with less distortion. Frequency Response: 25Hz - 135Hz (+/- 3dB) - Peak Power Handling: 4000 watts - Program Power Handling: 2000 watts - Max SPL: 144 dB - Nominal Impedance: 8 Ohms - Sensitivity (1w/1m): 108 dB • Connections: Neutrik Speakon™ • Stroker® 21" Woofer with 4" Voice Coil - Durable Multi-Ply Construction - High Quality Black Carpet for Durability • New cast aluminum door & steel cabinet bracing. Includes casters.