If you need to remove one of the terminals on a Weather Pack connector this tool makes the job a breeze.  Trying to remove it without a tool like this is virtually impossible without damaging the terminal or the housing.  Best have one of these in the tool box if you have any Weather Pack terminals on your ECU harness.  While most of the connectors on Holley harnesses are Metri Pack, they seem to manage to put at least one Weather Pack connector on each system they offer.