The 12 Volt 1.4 Watt fan is for use with the Excel AC/DC or Excel NE when there is down-draft present. This fan moves approximately 7 cfm.
The 12 Volt 2.4 Watt fan is for use with the Excel AC/DC or Excel NE when there is down-draft present. This fan moves approximately 7 cfm.
The 24 Volt 3.12 Watt fan is for use with non-electric toilets where a 24 volt system is in place.