JBL / Selenium / by Harman ST400 BLK Super Tweeter.Super tweeter for outstanding detail and clarity in high-frequencies without harshness. The ST400 BLK may be used individually in lower power systems or arrayed for increased coverage and SPL in higher power systems Specifications :Impedance (ohms) - 8RMS (W) - 150Musical Program (W) - 300SPL 1W @ 1m (dB) - 111Frequency Resp. @ -10dB (Hz) - 3.000 to 20.000Voice Coil Diameter - 1.7 (42)Sound Dispersion HxV - 40° x 40°Magnet weight (g) - 15 lbs (430)Diaphragm – Phenolic Annular Housing material - PlasticOverall Outside Diameter- 6"(152.4mm) x 4.75"(120.55mm) (See pics).Mounting Depth - 3.5" (88.9mm) (See Pics). Weight - 3.75 lbs FREE SHIPPING ONLY In the Lower 48 States.Most Orders Placed Before 2PM and Paid thru' PayPal Are Shipped The Same Day; Monday to Friday.