The Delta T controller is an optional accessory for dew prevention on CDK14 through CDK24 OTAs and the CDK700 system.
CDK12.5 to CDK24 and CDK700 telescopes come with primary and secondary mirror dew heating pads (CDK700 adds tertiary mirror heating), which are ready to accept the Delta T controller.
Controlled via PWI3 software for CDK12.5 through CDK24 OTAs (PWI2 for the CDK700).