This page details one of the two ways to utilize the #25 Chain Tool (REV-41-1442), using Master Links (REV-41-1366). The included 3mm Allen Wrench works on all three screws of the tool.
The image above gives a basic overview of how to secure the #25 Chain (REV-41-1365) using a master link. Follow the steps below to see how to use the chain tool and the master link to manipulate a chain to the size you want.
Unscrew the pin screw and compression screw such that they are flush with the chain channel.
Insert #25 chain (REV-41-1365) into the chain channel and align the desired link between the two vertical pins in the channel.
Next secure the chain in place with the compression screw. Tighten until the chain cannot shift within the channel.
With the chain in place it can now be broken. Turn the Allen Key until the pin is entirely removed from the chain. Make sure to have a master link on hand (REV-41-1366). You must have one empty link on either side; two plates will not work. The picture shows an example of this step at completion.
Remove the cup point set screw before breaking the chain. This will allow for the pin to completely remove itself from the chain.
Place the master link into both links. Next take the plate and put it over the master link. Use pliers and the included clip to lock the master link into place.