Sennheiser Evolution Wireless Digital Series Instruction Manual page 62

Using EW-D Color Coding Sets to label trans-
mission paths
You can use the EW-D Color Coding Sets (see „Color Coding
Sets") to identify which transmitters belong to which receiv-
ers. This makes it easier to match up the individual devices,
especially in multi-channel systems.
You can also assign colors to the devices in the EW-D
Smart Assist app.
EW-D SKM-S handheld transmitter
61