Valcomft. s V-9925A Loud warble horn features 90 vac ring 18 vac buzzer voltage activation and connects directly to PBX or station lines Built-In Tone Generator 5-Watt amplifier and volume control: Specifications: Power Requirements: -24 Vdc 500 mA: Activate with 90 Vac 18 Vac; Shipping Weight: 4.7 lbs (2.13 kg); Dimensions: 6.5in. H x 8.2in. W x 10.4in. D (16.51 cm x 20.82 cm x 26.4 cm)