One Systems POPS 15a - Manual (Page 15)

When the audio connectors are not in use the water covers should be inserted in
the XLR connector. (Example: If the audio input is being used but the audio thru
connector is not being used the water cover should be inserted in the audio thru
XLR)
The image above shows both the INPUT and THRU connections with their water
covers in place.
Connect the audio out from the console/mixer using the supplied XLR to XLR
cable.
POPS15a also features an audio output/thru. This connection MUST also use a
Neutrik NC3FXX-HD-D cable end connector. The picture below shows the water
cover removed from the image for clarity. The water covers are permanently
attached to POPS15a’s input plate and will hang down from the panel when not
inserted in the audio input or audio thru XLR connectors.
Input