Kidde KI-IB Isolator BaseThe Kidde KI IB Isolator Base includes a built in line fault isolator for use on Class A circuits. A detector must be installed for it to operate. The isolator base does not support the GSA LED Remote LED. Kidde KI IB Isolator Base is compatible for use with Kidde VS and VM series FACPs. KI Series detector bases mount to North American 1 gang boxes, 3 1 2 inch or 4 inch octagon boxes, and to 4 inch square electrical boxes 1 1 2 inches (38 mm) deep