The application is the most important information when determining which product the customer should use. Calmark and Birtcher have products that are idea for both sheet metal and cold wall applications. If a sheet metal application, is PCB retention is required? If board clamping is not required, there are two options: either a PCB Tainer or Nylon card guide. If board clamping is required, the best solution would be a wedge tainer or lok tainer. If the application has a cold wall, it is important to know whether the cold wall has machined slots for the PCBs. If the cold wall does not have cold wall gaps, then a wedge tainer or channel lok should be used. If the cold wall does have channels for the PCBs, then a card or wedge lok, or a lok tainer would be best.