Stainless Steel Stainless Steel AZ 30RDia: 30 mm, Height: 5 mmOutput: nom .4 watt and max .8 wattFrequency range: 1300-8000 Fo-HzImpedance: 8 ohms Stainless Steel AZ 40RDia: 40 mm, Height: 5 mmOutput: nom .4 watt and max .8 wattFrequency range: 600-6000 Fo-HzImpedance: 8 ohms