Source for Wizard/Merlin midiprep plastic columns?

[Jenny F.]

Hello everyone,

We use these columns to do a homemade Merlin/Wizard-type midiprep.  (In 
fact we just reuse the columns after getting rid of the resin.)  
Unfortunately, we've lost our last of these columns.  Promega has 
stopped selling the type that we use -- they've seemingly redesigned 
the columns so as to prevent reuse.  (They now have the resin collected 
in a narrowed part of the column toward the bottom, which you are 
supposed to physically separate in order to later elute... clever 
devils! Unfortunately, these new columns also work extremely poorly.)  
The type that we use is perhaps 50 mL total volume, bottom maybe 4mm 
diameter, bottom opening maybe 2mm diameter (this is important so they 
fit into the vacuum manifold).  They also have a relatively thick 
plastic frit at the bottom (important so that resin can't get through), 
which is the full size of the column diameter.  Anyone know of a source 
for these columns?

Thanks,

Jenny