- New high output speaker amplifier with volume adjustment POT- Microphone volume adjustment POT- 24V talk battery- 20Hz ring generator (3.0 REN ring load maximum)- Selectable number of rings (2, 3, 10, or 30)- Extended operating temperature range: -15 degrees F to 130 degrees F- Compact 45 degree terminal strip for easy wiring- Optional Enhanced Weather Protection (VK-W-1000-EWP)