Aluminum bell housing- Loud, Up to 95+ dB ring- Shell Size: 6 Inch Diameter- Rings from any standard size RJ-11 telephone line- NO AC Power required- Perfect for Indoor or Outdoor use- Includes Weatherproof backbox- Motor Driven- Tamper resistant volume control- Screw terminal connections and RJ-11 plug- Integral RFI suppression- Ringer Equivalence Number REN: 1.6A- Approvals Include: TB-593 is UL Listed- Dimensions: 6.062In. Diameter x 4.21 Depth