RDL RU-MX4L Pro 4 Input Line Mixer - Mic and Line OutThe L is the ideal choice in many applications where a combination of balanced and or unbalanced line level signals needs to be mixed. Balanced connections use XLR connectors. Unbalanced signals are coupled through phono jacks. Each of the four L inputs can accept either a balanced XLR line level input or an unbalanced line level phono jack input. The unbalanced phono jack LINE OUTPUT from one L may connect to the unbalanced input of other equipment,