New base for the 1617/1618 series routers</br>Allows adjustment of bit height from above the table</br>Wrench access from above table for convenient depth adjustment</br>Base has threaded holes for mounting to router table</br>Wide 3-3/4 base opening allows use of larger bits</br></br>Product Description</br></br>BOSCH Router Undermount Ba</br></br>Amazon.com</br></br>The RA1165 under-table base is based on the durable Bosch fixed base but enhanced with an above-table bit height adjustment mechanism. The RA1165 under-table base can be mounted to virtually any table surface and common router table plates.</br><br/>http://www.amazon.com/gp/product/B0007VHPFK