The transmitter (the body-pack device) needs 2pcs AA 1.5V batteries, while the receiver (the part being plugged into the speaker) uses 2pcs AAA 1.5V batteries.

Generally, it could last 5 to 6 hours with fresh alkaline batteries or fully charged rechargeable batteries. But different batteries vary a bit because of different capacities.

We suggest you try other brand-new batteries to find the most durable ones. And please turn off both the transmitter and receiver to save power between services. Also, take out the batteries if you don’t use the mic for a long time.