A template guide is used for following templates when routing. The guide fits into the base of a router designed to accept it. Ours fit Porter Cable routers. If oyu have a router other than Porter Cable you may want to check with the manufacture to see if these will fit.
The template fits into the center hole on the base and a threaded ring is attached to hold it in place. A router bit with a smaller diameter than the inside of the template guide passes through the guide. The guide rides against the straight edge or template as the router bit cuts the material. Our guide are specially made to work with materials as thin as 5/16".