Audio Technica AT841A 
Superb plate mic

Ex demo, fully working, with battery phantom power pack, cable, pouch and lead

Specifications

• Element: Fixed-charge back plate permanently polarized condenser
• Polar Pattern: Omnidirectional in hemisphere above mounting surface
• Frequency Response: 30-20,000 Hz
• Low Frequency Roll Off: 80 Hz, 18 dB/octave
• Open Circuit Sensitivity: Phantom: -39 dB (11.2 mV) re 1V at 1 Pa Battery: -40 dB (10.0 mV) re 1V at 1 Pa
• Impedance: Phantom: 200 ohms Battery: 270 ohms
• Maximum Input Sound Level: Phantom: 132 dB, 1 kHz at 1% T.H.D. Battery: 122 dB SPL, 1 kHz at 1% T.H.D.
• Dynamic Range: Phantom: 111 dB, 1 kHz at Max SPL Battery: 101 dB, 1 kHz at Max SPL
• Signal to Noise Ratio: 73 dB, 1 kHz at 1 Pa
• Phantom Power Requiremens: 11-52V DC, 2 mA typical
• Battery Type: 1.5V AA/UM3
• Battery Current Life: 0.4 mA / 1200 hours typical (alkaline)
• Switch: Off, on-flat, on-roll-off
• Cable: 25.0' (7.6 m) long (permanently attached to microphone), 0.13" (3.2 mm) diameter, 2-conductor, shielded cable with TA3F-type connector
• Accessories: AT8531 power module; battery; soft protective pouch