You can keep your current extension wings in place and add this plate on the end of the outer most wings. Alternatively you can remove the current plate and bolt this one on. There are three pre-drilled holes on the router extension wing, but if they don't line up, don't worry, because cast iron can be drilled with a standard drill and twist drill bit.
It will on table saws that have a mitre slot 685mm (27in) long without any modification. If your mitre slot is longer or shorter than this, you may need to cut the plate down to size or fill in the gap between the plate and your fence with a piece of timber or metal.
There are T-channels running underneath the router plate and a set of clamps to hold the router in place are included. Because of the way the T-channels are cast into the underside of the plate it will suit all plunge routers.
The hole diameter on the plate is 90mm, with two insert rings included - 1x 30mm diameter hole & 1x 60mm diameter hole.