The standard zero-clearance insert can be used to replace the insert included with your saw if it becomes damaged, or to create dedicated inserts for each of your blades. Positioning screws and a concealed positive locking latch ensure a tool-free, precise and snug fit in the saw's table. The insert comes with clearance slots for the blade guard and riving knife; so, once it is installed, simply raise the running blade through the insert to create a zero-clearance blade slot. Made of a glass filled nylon.