EPOS ELS Bookshelf Speaker Power Handling 100 Watts Max - Frequency Response 65Hz - 20kHz Impedance 4 Ohms Nominal - Sensitivity 87dB/ 1 watt/ 1 meter- Amplifier Compatibility: 25 - 100 Watt 5 year warranty Woofer-Midrange - 130 mm Diecast Aluminum Frame Tweeter  25mm aluminum dome with Polyamide suspension