Sylvia:


                                flange  diameter
                       nipple tunnel

  Ameda Egnell                       3"                                     1
1/4"

  Medela'a                             3 1/8"
                                 7/8"

  Nurture 3                               3"
                                     1"

  White River                          2 3/4"
                                  3/4"

   - from kittie frantz' bf product quide -

        Patricia