Kidde KI-ABLT Low Frequency Sounder BaseKI Series sounder bases are designed for use where localized or group alarm signaling is required. KI ABLT bases provide 520 Hz low frequency sounder capability to KI Series smoke and heat detectors, as well as carbon monoxide detectors when used with a GSA T3T4 Temporal Pattern Generator. The KI ABLT is suitable for applications requiring low frequency audible tones.