Phase-inverted design, built-in acoustically measured-inverted tube, effectively improve the performance of low and medium frequency. Specifications: Brand Name: Summer Audio S3 Type: Speaker Color: White/Black(Optional) Material: MDF Frequency Response Range: 118Hz-18KHz Power: 5-30W Sensitivity: 88dB Impedance: 4 ohm Package Size: 302319.5cm / 220.127.116.11in Package Weight: 3725g / 131.4oz Package List: 2 Speaker.Thank you for your understanding. Feedback is very very important to us. We will response in 24 hours to resolve the problems. The negative / neutral feedback and low DSR scores are of very negative effect on our account status. We will surely try our best to resolve the problem to your satisfaction! This item is in the category "Sound & Vision\Home Audio & HiFi Separates\Speakers & Subwoofers". The seller is "kevin920406b" and is located in this country: CN. This item can be shipped worldwide.