The BZR regulator series is available for precise control of ambient temperatures up to a continuous operating range of 150° F (Model BZR-150). For heated gases or higher ambient operating conditions, models BZR-300, BZR-500 and BZR-700 are available.

Selas Model BZR-B uses a gas adjuster downstream of a negative biased regulator, so high fire can be set to stoichiometric conditions. As the system is turned down, the spring bias will subtract from the combustion air pressure causing the burner to go lean. Model BZR-B-300 is available for up to 300° F service.

The Selas Gas-Lok is a modification of the Zero Governor enabling its use as both a precision balanced regulator and operating shutoff valve.