Mains powered - designed to increase a REN of 4 to a REN of 11. The ideal choice when you need to ring several items...telephones, fax machine, answering machine, etc.
Adjustable ringer up to 95db. The user can adjust the sound to their preferences. Bright visual ring indicator, Choice of 4 ring patterns, Battery back-up
Line powered, for installation in offices or factories with high ambient noise levels. Has a volume control up to 105 dB. Waterproofed to standard IP66.