1.8 Inch car subwoofer with Iron frame, 2.dual 4ohm, 3.300W, 600W(Max) VW08-020R8 Inch car subwoofer with Iron frame ... 3RESONANCE FREQUENCY40Hz± 20% Hz at 1 V4RATED FREQUENCY RANGE (E.F.R.) F0 ~ 1 KHz -10dB5SOUND PRESSURE LEVEL84dB/ 1w/ ... 3,9 after test.13HEAT TEST55±2°C for 8+Room ambient condition for 1h.The speaker must meet ... test.15FRAME 16VOICE COIL Φ50Voice Coil 17EDGEPP 600W 8 Inch car subwoofer