Solid State Logic SSL 18 User Manual page 25

AUX Masters
The Aux Masters section of the Mixer View consists of Headphones A, Headphones B & Line Out 3-4 Aux Master Outputs.
Headphone Outputs
Each Headphone Output consists of a large Signal Metering section with a resolution from 0dB down to -60dB.
Below are details of the Fader section with the following parameters:
1. SENDS POST
When selected, send levels to the aux busses from the channels will be Post Fader level.
2. FOLLOW MIX 1-2
Over-rides the aux master so that it follows the Monitor Bus mix, providing an easy way to send what you are listening to on the
Monitor Bus (through your monitor speakers) to the Headphones.