Hi Marc,
     I've been using Imirie Shims for five years and love them. When You add
drawn supers put the shim above the queen excluder as an upper entrance,
they can be put between drawn supers also. You must remove the super as soon
as it is filled,  You can not leave it for an extended period or the bees
will build burr comb.

I use shims year round on top of the inner cover as an entrance and  to aid
in ventilation.

Also, You can put two on an inner cover to use as a baggie feeder(if robbing
is a concern You wrap masking tape around the opening side).

When stacking supers to store You can staple plastic window screen on the
solid edge to make a screen to keep out wax moths and other insects and use
one on the top and one on the bottom. You could use screened ones in between
to place moth crystals on too.
George Imirie invented a very useful gadget when He thought up the shim.
Thank You George.
Sincerely,
Garry Libby
Attleboro, Massachusetts, USA
41.56 N    71.17 W
<mailto:[log in to unmask]>