Champion manufactures a complete line of takeoffs for residential or light commercial applications.  The last dimension in the description is the collar size.  Each takeoff has a consistent cut out dimension and all round fittings have divider points on the back of the base for easy setting of hole cutters.  "Rise" of takeoffs when installed: 572 - 3/4"; 575 - 1 1/4; 568 - 1 1/4"; 577 - 1 7/8"; 577 w/1/2 tab - 1 7/8"; 577 QT - 1 1/4".  502 - 503 start collars have a length of 2" when installed.