RT/RTR and RJ/RJR series trim pots are made to military specifications and are listed on the QPL (Qualified Parts List). Which simply means that they are on a government approved list of parts that are approved for government and military use. RT/RJ series trim pots are made to the MIL-PRF-22097 and the RTR/RJR series trim pots are made to the MIL-PRF-39035. The major difference between RT/RJ and the RTR/RJR series is that the RTR/RJR trim pots are offered with a failure rate. A failure rate is the frequency at which a component fails during testing over a set period of time.
RTR/RJR series of trim pots are offered in three failure rate levels:
Note: Failure per 1000 hours of testing.
Although the RJ/RJR series and the RT/RTR series look pretty much identical, they have two different restive elements used for the resistive track that the wiper follows.
All the series of trim pots mentioned above are a sealed style trim pot, which means that the resistive track and the wiper are covered by a protective material. Depending on the configuration, these trim pots may have a temperature rating of -55°C to 150°C or -65°C to +150°C. Due to their small size trim pots are very fragile, and most manufactures rate their lifespan at 200 cycles so frequent adjustments are not recommended.