Looking to add another frequency-agile UHF wireless system to your Expedition XP310w or XP312w Rechargeable Portable PA? The Concert 88a Series features Concert 88 Series wireless transmitters and the unique CR88a Receiver Module, which is specifically designed to slide/lock into the back panel of your XP310w or XP312w. Concert 88a Series wireless system is available in Handheld, Lavalier and Headset microphone configurations.