Good Morning Becky,
I got to my pumps with the pressure gauge(Ispelled it right this time) this
morning and this is what I found out.  I tested both the Lactina, using the
Select this time to see if there might be any difference when changing speed,
and the Classic.  I tested both through the breastshield and still found a
marked difference with the Classic being considerably stronger, particularly
when used at the highest pressure.  There is also a difference at the lowest
pressure but not quite as profound.  There was no difference with the Lactina
Select when changing speeds, which of course, there should not be.

After reading Kathleen A's comment on Chapter 11 in Riordan and Auerbach, I
went to the book this morning and checked out Table 11-5, pages 298-299 -
Selected Technical Data on Pumps.  Down at the bottom of the chart the large
automatic pumps are listed with range of pressures.  There surely is a
difference in pressure noted in this table for different pumps.  However, with
Medela, there is not a differentiation noted for the Classic and the Lactina.
It was definately interesting checking this Table out at this time with all the
discussion on pump pressure.  I hope you will get back to us and let us know
how exactly you have tested which results in the same pressure.  We did use the
rubber stopper technique checking both pumps at the breast shield level.

Yaffa Stark, MA, IBCLC