The Kodalux mailer program has been shut down, but slide film mailers such as this one will be honored through the end of 2009 if they haven't expired.  Mail them to

Kodak Processing
c/o Dwayne's Photo
PO Box 1171
Parsons, KS  67357.

The PK-12 mailer had two purposes.  The most straightforward was processing of 120 film, which has 12 6-by-6 exposures per roll.  The other was combining with a PK-24 mailer to process a 36-exposure roll of 135 film.  Complaints used to circulate about inconsistent processing of 120 film at the Qualex plant, but all processing is now handled by Dwayne's.  I haven't processed any 120 through them, but have no complaints about their handling of 135 film.  If you like Dwayne's handling of 120, these mailers are a way to obtain it at a discount, or a way to get 36-exposure 135 processing by addition.

Recommended: Yes